JP2003164186A - Motor drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive device which can surely protect a switching element, even if a non-insulated power supply with a simple structure is used as a power source to supply DC power to the switching element. <P>SOLUTION: A motor drive device 22 which generates a current signal by switching on and off switching elements 5a and 5b corresponding to a pulse width modulation signal and outputs the current signal to a drive objective motor 23 comprises: a non-insulated power supply 33 which has a rectification diode 3a and an output capacitor 3c, converts AC power to DC power, and supplies the DC power to the switching elements 5a and 5b; an electromagnetic relay including a make contact 2a which intermittently connects the supply route of the AC power to the non-insulated power supply; and discharge means 34 and 2b which discharge the electric charge of the output capacitor 3c when the make contact is switched to an open state to break the supply route. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device for driving a motor, and more particularly to a motor drive device suitable for use under a condition of strict positioning accuracy such as semiconductor manufacturing technology.

[0002]

2. Description of the Related Art Conventionally, a pulse width modulation (PWM) type motor drive device has been known. This motor driving device is mounted in, for example, an exposure device used in a manufacturing process of semiconductor elements, liquid crystal devices, etc., and is used for driving a motor of a stage that moves a wafer (exposure target), a reticle (mask), and the like.

As is well known, a PWM type motor drive device generates a current signal by turning on / off a switching element according to a PWM signal, outputs the obtained current signal to the motor, and drives this motor. It is a device that does.
Further, in the PWM type motor drive device, an insulating power source such as a switching regulator type is generally used as a power source for supplying DC power to the switching element. This isolated power supply is a stabilized power supply with isolated input and output, converts AC power on the input side into desired DC power, and supplies the converted DC power to the above switching element connected to the output side. To do.

[0004]

However, in the motor drive device using the above-mentioned insulated power supply as the power supply for the switching element, the current signal to be output to the motor is increased as the output power of the motor to be driven increases and the accuracy increases. Is increased,
The DC power supplied to the switching element has to be increased, and in order to cope with this, the insulation power supply has been increased in size and the price has been improved. Further, the volume and price of the insulating power source occupy a high proportion in the motor drive device, and the motor drive device also becomes larger and the price increases as the insulating power source becomes larger and more expensive.

Therefore, in recent years, it has been considered to use a non-insulated power source having a simple structure composed of a rectifying diode and an output capacitor, instead of the above-mentioned insulated power source, to reduce the size and cost of the motor drive device. ing. However, since the input / output of the non-insulated power supply is not insulated, the switching element may be destroyed by the energy accumulated in the output capacitor.

An object of the present invention is to provide a motor drive device capable of reliably protecting a switching element even when a non-insulated power source having a simple structure is used as a power source for supplying DC power to the switching element.

[0007]

According to a first aspect of the present invention, a motor for generating a current signal by turning on / off a switching element according to a pulse width modulation signal and outputting the current signal to a motor to be driven. The drive device has a rectifying diode and an output capacitor, and intermittently connects a non-insulated power supply that converts AC power to DC power and supplies the DC power to the switching element, and a supply path of the AC power to the non-insulated power supply. An electromagnetic relay including a make contact, and a discharging unit that discharges the electric charge of the output capacitor when the make contact is switched to an open state that cuts off the supply path.

According to a second aspect of the present invention, in the motor drive apparatus according to the first aspect, the discharging means is composed of a discharging resistor and a discharging switch connected in series at both ends of the output capacitor, The electromagnetic relay includes a break contact whose open / closed state is opposite to that of the make contact, and the break contact is used as the discharge switch.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The embodiment of the present invention corresponds to claims 1 and 2. Before describing the motor drive device according to the present embodiment in detail, the overall structure of a stage device and an exposure apparatus incorporating the motor drive device will be briefly described.

As shown in FIG. 1, the exposure apparatus 10 has a stage 11 on which a semiconductor wafer 12 to be exposed is mounted.
And a stage controller 15 for controlling the stage 11. A projection optical system 13 is provided above the stage 11, and a reticle stage 13b is provided above the projection optical system 13. Reticle stage 13b
Is for mounting the reticle 13a.

Further, the exposure apparatus 10 includes a stage controller 16 for controlling the reticle stage 13b and a TTR.
(Through the reticle) type position measuring unit 14a, 1
4b, TTL (through-the-lens) type position measuring units 14c and 14d, and off-axis type position measuring units 14e and 14f. Position measuring unit 14
Reference numerals a and 14b are for observing the mark on the reticle 13a and the alignment mark on the stage 11 side in an overlapping manner via the reticle 13a and the projection optical system 13. The position measuring units 14c and 14d are for observing the alignment mark on the stage 11 side via the projection optical system 13. The position measuring units 14e and 14f are for directly observing the alignment mark on the stage 11 side without going through the projection optical system 13 or the like.

Further, the exposure apparatus 10 includes a position control section 21 for independently controlling the stage control sections 15 and 16, and a stage 11 and a reticle stage 13 for the position control section 21.
An upper control unit (not shown) for outputting the target position information of b is provided. The position control unit 21 includes the position measurement units 14a to 14a.
In order to realize the speed and position accuracy when moving the stage 11 to the target position based on the current position information from 4f and the target position information from the upper control unit (not shown), A required motor thrust (a required thrust to the motor 23 described later) is determined.

Then, the position control section 21 generates an input voltage signal for wafer position control based on the motor thrust force (requested thrust force to the motor 23) determined as described above, and this is input to the stage control section 15. Output. The position control unit 2
From 1 to the stage controller 15, the enable signal (ENA) is output in addition to the input voltage signal for controlling the wafer position.

Further, the position control unit 21 determines the speed and position accuracy when moving the reticle stage 13b to the target position based on the above-mentioned current position information and target position information, and in order to realize this. A required motor thrust (a required thrust to the motor 26 described later) is determined.

Then, the position control unit 21 generates an input voltage signal for controlling the reticle position based on the motor thrust force (requested thrust force to the motor 26) determined as described above, and this is input to the stage control unit 16. Output. In addition to the input voltage signal for controlling the reticle position, the enable signal (ENA) is output from the position control unit 21 to the stage control unit 16.

Further, the stage control section 15 is arranged so that the stage 1
It is composed of a motor drive device 22 for 1, a motor 23, and a positioning mechanism 24. The motor drive device 22 for the stage 11 is a PWM type motor drive device that generates an output current signal that is substantially proportional to the input voltage signal (a signal representing the required thrust force to the motor 23) from the position control unit 21 described above. The motor 23 is driven based on the generated output current signal (details will be described later). Then, the positioning mechanism 24
Uses the motor 23 as a power source to drive the stage 11 in a two-dimensional direction to position the semiconductor wafer 12.

On the other hand, the stage controller 16 includes a motor driving device 25 for the reticle stage 13b and a motor 26.
And a positioning mechanism 27. The motor drive device 25 for the reticle stage 13b generates an output current signal that is substantially proportional to the input voltage signal (a signal representing the required thrust force to the motor 26) from the position control unit 21 described above.
It is a WM type motor drive device (details will be described later), and drives the motor 26 based on the generated output current signal.
Then, the positioning mechanism 27 uses the motor 26 as a power source to drive the reticle stage 13b in the two-dimensional direction,
The reticle 13a is positioned.

The enable signal (ENA) output from the position controller 21 to the stage controllers 15 and 16 respectively.
Is a command signal for bringing the motor drive devices 22 and 25 into a drivable state. Further, when the enable signal is disabled, it is a command to put the motor drive devices 22 and 25 into a ready state.

The exposure apparatus 10 configured as described above is
Since the stage 11 for the semiconductor wafer 12 and the reticle stage 13b for the reticle 13a can move independently,
It can be used in both a scanning type and a fixed type. Now then
The motor drive device 22 for the stage 11 and the motor drive device 25 for the reticle stage 13b described above will be described in detail with reference to FIG. FIG. 2 is a block diagram showing the internal configuration of the motor drive devices 22 and 25.

The motor drive devices 22 and 25 include a circuit breaker 31, a contactor 32, a high-output non-insulated power supply 33, a discharging resistor 34, and a switching circuit 35.
, Smoothing circuit 36, detection resistor 37, and control circuit 38
And a small output control circuit power supply 39.
First, the circuit breaker 31, the small output control circuit power supply 39, and the control circuit 38 will be sequentially described, and then the contactor 32, the large output non-insulated power supply 33, the switching circuit 35, the smoothing circuit 36, and the detection resistor. 37 will be sequentially described, and finally the discharge resistor 34 will be described.

The circuit breaker 31 is a main switch of the motor drive units 22 and 25, and is connected to the motor drive units 22 and 25 from an external main power source (three-phase 200V AC power source).
When the AC power is supplied to 25, it is manually closed to be in the closed state (ON). Also, when an abnormal current flows, it automatically opens (OFF). Small output power supply for control circuit 3
Reference numeral 9 is an insulated power supply such as a switching regulator system. When the circuit breaker 31 is closed, AC power (200 V AC) from the main power supply is converted into desired DC power (DC2).
4V) and supplies the converted DC power to the control circuit 38.

However, it takes a certain amount of time from the timing when the circuit breaker 31 is closed until the DC power converted by the control circuit power supply 39 reaches a desired voltage value (DC24V).

On the contrary, when the circuit breaker 31 is changed from the closed state to the open state, the voltage value of the DC power supplied from the control circuit power source 39 to the control circuit 38 changes from 24V DC to 24V DC as shown in FIG. 3 (a). Gradually descend. The control circuit power supply 39 is an insulating power supply such as a switching regulator system, but since it has a small output (DC24V), it can be small and inexpensive.

The control circuit 38 can operate normally when the DC power supplied from the power supply 39 for the control circuit has a constant voltage value (for example, 15 V) or more. This control circuit 38
The enable signal (ENA) is input to (FIG. 2) from the position control unit 21 described above. As described above, the enable signal is a command signal for setting the motor drive devices 22 and 25 in a drivable state. When the enable signal is input, the control circuit 38 controls the contactor 32 to close the make contact 2a (described later). As a result, the motor drive devices 22 and 25 are ready to be driven.

Further, the input voltage signal is input to the control circuit 38 from the position control section 21. As described above, the input voltage signal is a signal representing the thrust required of the motors 23 and 26. Further, the control circuit 38 is supplied with a current detection signal corresponding to a voltage drop in the detection resistor 37 (described later). This current detection signal is sent to the motor 2
3, 26 is a signal that represents the thrust that is actually generated.

The control circuit 38 generates an error signal based on the difference between the amplitude of the input voltage signal (the magnitude of the required thrust) and the amplitude of the current detection signal (the magnitude of the actual thrust). A PWM signal is generated by comparison with a reference signal (triangular wave signal or sawtooth wave signal). The PWM signal has a duty ratio (ratio between H level and L level) modulated according to the amplitude of the error signal. Then, the control circuit 38
The switching elements 5a and 5b (described later) of the switching circuit 35 are alternately conductively controlled according to the PWM signal.

The control circuit 38 (1) when the enable signal is disabled, or (2) when the amplitude (the magnitude of the required thrust) of the input voltage signal becomes 0, or ( 3) When the circuit breaker 31 is opened, the contactor 32 is controlled to open the make contact 2a (described later). As a result, the motor drive device 2
2,25 are ready.

The contactor 32 includes a make contact 2a, a break contact 2b, and a relay coil 2c.
It is an electromagnetic relay composed of and. Further, the control circuit 38 is connected to the relay coil 2c. Incidentally, the control circuit 38 supplies a current to the relay coil 2c of the contactor 32 in order to bring the motor drive devices 22 and 25 into a drivable state. Further, in order to bring the motor drive devices 22 and 25 into a ready state, the relay coil 2c
To stop the supply of current to.

From the control circuit 38 to the relay coil 2
When current is supplied to c, the make contact 2a is closed and the break contact 2b is open. This state is called the metastable state of the contactor 32. When the supply of current to the relay coil 2c is stopped, the make contact 2a is open and the break contact 2b is closed. This state is called the stable state of the contactor 32.

When the contactor 32 is in the metastable state, the make contact 2a and the circuit breaker 31 are connected to the non-insulated power source 33 (described later) connected to the subsequent stage of the contactor 32.
The external main power supply (3 phase 200
AC power is actually supplied from the V AC power supply). Then, the motor drive devices 22 and 25 are in a drivable state.
Also, when the contactor 32 is in a stable state, the make contact 2
The open state of a means that the supply path of the AC power from the main power supply (AC power of three-phase 200V) to the non-insulated power supply 33 is cut off. Then, the motor drive device 22,
25 is in a ready state.

The break contact 2b of the contactor 32
Indicates that the open / closed state is opposite to that of the make contact 2a, and the contactor 32 is in a metastable state (motor drive device can be driven).
When the contactor 32 is in the stable state (the motor drive device is in the ready state), it is in the open state. The break contact 2b is used as a discharge switch (details will be described later).

The high-output non-insulated power supply 33 is a power supply having a simple structure which is composed of a rectifying diode 3a, a power factor improving choke coil 3b and an output capacitor 3c, and its input side and output side are not insulated. . Output capacitor 3c
Is provided mainly for the purpose of reducing ripple. The non-insulated power supply 33 may be provided with a line filter or a fuse.

In this non-insulated power supply 33, the contactor 32 is in a metastable state (motor drive device can be driven),
When the make contact 2a is in the closed state, the AC power (AC200V) of the main power supply is changed to the desired DC power (DC28 of high voltage HV).
0 V) and supplies the converted DC power to the switching circuit 35. The switching circuit 35 includes switching elements 5a and 5b. The switching elements 5a and 5b are MOSFET switching elements or I
It is a GBT switching element. Switching element 5
The gates of a and 5b are connected to the control circuit 38, respectively. Incidentally, the control circuit 38 alternately controls the conduction of the switching elements 5a and 5b according to the above-mentioned PWM signal.

Therefore, when the PWM signal is at the H level, one switching element 5a becomes conductive (ON) and the other switching element 5b becomes non-conductive (OFF).
On the contrary, when the PWM signal is at the L level, one switching element 5a becomes non-conductive and the other switching element 5b becomes conductive. Then, the switching element 5a
When the switching element 5a is in the conductive state, a current flows from the switching element 5a to the smoothing circuit 36, and conversely, when the switching element 5b is in the conductive state, a current flows from the smoothing circuit 36 to the switching element 5b. As a result, the PWM signal generated by the control circuit 38 is the DC power supplied to the switching circuit 35 (DC 280V of high voltage HV).
Power is amplified by.

The smoothing circuit 36 is a low pass filter (LPF) composed of a coil 6a and a capacitor 6b. The smoothing circuit 36 is a circuit that smoothes the power-amplified PWM signal, removes the fundamental frequency component and harmonic components of the PWM signal, and generates an output current signal. The output current signal from the smoothing circuit 36 is supplied to the motors 23 and 26 via the minute detection resistor 37.
Then, in the motors 23, 26, the motor drive devices 22, 2
According to the output current signal obtained from 5, thrust is actually generated. The output current signal supplied to the motors 23 and 26 is fed back to the control circuit 38 via the detection resistor 37 and used to generate the error signal.

Finally, the discharging resistor 34 will be described. The discharge resistor 34 is connected in series with the break contact 2b of the contactor 32 described above. Discharge resistor 34
And the break contact 2b are collectively referred to as a discharge circuit (34, 2b). The discharging circuit (34, 2b) corresponds to the "discharging means" in the claims. The discharge circuit (34, 2b) is connected to both ends of the output capacitor 3c of the non-insulated power supply 33. Therefore, when the break contact 2b is in the closed state, a closed circuit including the break contact 2b, the discharging resistor 34 and the output capacitor 3c is formed, and the electric charge of the output capacitor 3c is discharged through the discharging resistor 34. Conversely, break contact 2
If b is in the open state, the electric charge of the output capacitor 3c is held as it is. That is, the break contact 2b functions as a discharge switch.

As described above, the break contact 2b is closed when the contactor 32 is in a stable state (motor drive device is in a ready state), and the make contact 2a is open. Further, the break contact 2b is opened when the contactor 32 is in the metastable state (motor drive device can be driven), and the make contact 2a is closed.

Therefore, when the motor drive devices 22 and 25 are in a drivable state, stable DC power (high voltage HV of a high voltage HV is supplied from the non-insulated power supply 33 to the switching circuit 35.
DC280V) is supplied. When the switching elements 5a and 5b are alternately turned on and off according to the PWM signal from the control circuit 38, the PWM signal is power-amplified and an output current signal to the motors 23 and 26 is generated. This output current signal is an input voltage signal from the position control unit 21 to the control circuit 38 (request thrust force to the motors 23 and 26).
Is a signal approximately proportional to.

Therefore, the thrust force actually generated by the motors 23 and 26 in response to the output current signal is substantially equal to the input voltage signal from the position control unit 21 (the required thrust force to the motors 23 and 26). . As a result, the speeds of the stage 11 and the reticle stage 13b driven by the motors 23 and 26 as power sources also substantially match the speed determined by the position control unit 21 based on the current position information and the target position information. .

On the other hand, the control circuit 38 (1) when the enable signal is disabled, or (2) when the amplitude of the input voltage signal (the magnitude of the required thrust) becomes 0, or ( 3) When the circuit breaker 31 is opened, the motor drive devices 22 and 25 are brought into a ready state, so that the supply of current to the relay coil 2c of the contactor 32 is stopped.

As a result, the contactor 32 is switched to a stable state, the make contact 2a is opened and the break contact 2b is closed. As a result, a closed circuit composed of the break contact 2b, the discharging resistor 34, and the output capacitor 3c of the non-insulated power supply 33 is formed, and the charge of the output capacitor 3c is discharged through the discharging resistor 34. The discharging of the output capacitor 3c proceeds with a time constant according to the product of the capacitance of the output capacitor 3c and the resistance value of the discharging resistor 34. Then, as the discharge of the output capacitor 3c progresses,
As shown in FIG. 3B, the voltage value across the output capacitor 3c gradually drops from the high voltage HV of DC 280V.

Here, as described in (3) above, when the circuit breaker 31 is in an open state (during an emergency stop such as a power failure), the DC power supplied from the control circuit power supply 39 to the control circuit 38. As shown in FIG. 3A, the voltage value of
It gradually drops from 24V DC. Then, the DC power supplied from the control circuit power supply 39 to the control circuit 38 is
When the voltage value V1 (for example, 15 V) that guarantees the normal operation of the control circuit 38 becomes lower than or equal to, the operation of the control circuit 38 becomes unstable (down state) and unpredictable and uncertain for the gates of the switching elements 5a and 5b. A voltage may be applied, that is, the switching elements 5a and 5b may be simultaneously turned on.

Furthermore, at this time, a large amount of electric charge remains in the output capacitor 3c of the non-insulated power supply 33, and the voltage value (FIG. 3 (b)) across the output capacitor 3c has not dropped sufficiently. The energy stored in the output capacitor 3c may destroy the switching elements 5a and 5b. Therefore, when the output capacitor 3c of the non-insulated power supply 33 is discharged in consideration of the time T1 (FIG. 3 (a)) taken from when the circuit breaker 31 is in the open state until the control circuit 38 is in the down state. It is preferable to determine the time constant of

That is, within the above time T1, the voltage value across the output capacitor 3c of the non-insulated power supply 33 (FIG. 3 (b)).
However, the discharge time constant of the output capacitor 3c of the non-insulated power supply 33 is determined so that it becomes smaller than the safe voltage value V2 that does not damage the switching elements 5a and 5b.
Since the discharge time constant is determined according to the product of the capacitance of the output capacitor 3c and the resistance value of the discharge resistor 34, the determination of the time constant is nothing but the determination of the resistance value of the discharge resistor 34.

By determining the resistance value of the discharging resistor 34 in this manner, even if the circuit breaker 31 is in the open state at the time of an emergency stop such as a power failure, within the time T1 until the control circuit 38 is in the down state. In addition, the voltage value of the output capacitor 3c of the non-insulated power supply 33 can be made smaller than the safe voltage value V2. Therefore, in the motor drive devices 22 and 25 of the present embodiment, even when an unpredictable uncertain voltage is applied to the gates of the switching elements 5a and 5b from the control circuit 38 after the down state,
The switching elements 5a and 5b are not destroyed.

Further, when the circuit breaker 31 is switched from the open state to the closed state, the control circuit power source 3
DC power after conversion by 9 is the desired voltage value (DC24V)
It takes a certain amount of time to reach the following condition, and if the voltage value is V1 or less that guarantees the normal operation of the control circuit 38, the control circuit 3
8 may apply an unpredictable and uncertain voltage to the gates of the switching elements 5a and 5b.

However, the motor drive device 2 of this embodiment
In Nos. 2 and 25, when the circuit breaker 31 is switched from the open state to the closed state, there is no charge remaining in the output capacitor 3c of the non-insulated power supply 33 to the voltage value V2 or more. , 5
Even if an unpredictable and uncertain voltage is applied to the gate of b, the switching elements 5a and 5b are not destroyed.

In the above embodiment, the break contact 2b of the contactor 32 is used as the discharge switch, but a discharge switch may be provided separately from the break contact 2b. Also in this case, the discharging switch is connected in series with the discharging resistor 34. Further, the opening / closing control of the discharge switch is preferably performed in synchronization with the opening / closing control of the contactor 32.

Further, in the above embodiment, the motor 2
Although an example has been described in which the output current signal to the motors 3 and 26 is fed back to approach the input voltage signal (the required thrust to the motors 23 and 26), the feedback circuit is not always necessary. In this case, the accuracy of the output current control is reduced, but the device can be simplified.

[0050]

As described above, according to the motor drive device of the present invention, the switching element can be reliably protected even when a non-insulated power supply having a simple structure is used as the power supply of the switching element. Reliability can be improved as well as size reduction and price reduction.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an exposure apparatus 10.

FIG. 2 is a diagram showing an overall configuration of motor drive devices 22 and 25.

FIG. 3 is a diagram showing changes over time in the output voltage (a) of the control circuit power supply 39 and the output voltage (b) of the non-insulated power supply 33.

[Explanation of symbols]

10 Exposure equipment 11 stages 12 Semiconductor wafer 13a reticle 13b reticle stage 14a to 14f Position measuring unit 15, 16 Stage control unit 21 Position controller 22,25 Motor drive device 23,26 motor 24,27 Positioning mechanism 31 circuit breaker 32 contactors 2a Make contact 2b Break contact 2c relay coil 33 Non-isolated power supply 3a Rectifying diode 3b Power factor improving choke coil 3c output capacitor 34 Discharge resistor 35 Switching circuit 36 Smoothing circuit 37 Detection resistor 38 Control circuit 39 Control circuit power supply

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Claims (2)

[Claims] 1. A motor drive device for generating a current signal by turning on / off a switching element according to a pulse width modulation signal and outputting the current signal to a motor to be driven, comprising a rectifying diode and an output capacitor, A non-insulated power supply that converts AC power into DC power and supplies the DC power to the switching element, an electromagnetic relay that includes a make contact that connects and disconnects the supply path of the AC power to the non-insulated power supply, and the make contact. A motor driving device, comprising: a discharging unit that discharges the electric charge of the output capacitor when switched to an open state that shuts off the supply path. 2. The motor drive device according to claim 1, wherein the discharging unit includes a discharging resistor and a discharging switch connected in series at both ends of the output capacitor, and the electromagnetic relay is the make-up device. The motor drive device includes a break contact whose opening and closing state is opposite to that of the contact, and the break contact is used as the discharge switch.