JPH11164589A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable, if an instantaneous power interrupt or a power interrupt occurs in a power supply, prevention of free-running of a motor and decelerate and stop the motor within a fixed time, through inexpensive, simple constitution. SOLUTION: If an instantaneous power interrupt or a power interrupt occurs in an alternating current power supply 37, and an undervoltage signal UV is turned on, a constant time decelerating means 35 installed in a controlling means 23 opens contacts 29, 30 for invalidating an operation command ST and a speed command value FC from the external. A deceleration rate for stopping a motor in a certain constant deceleration time (t) (deceleration time (td): defined as the time required from the highest frequency FH to stop) is calculated from the output frequency (f) of an accelerating and decelerating means 31 at that time, using the following equation, and is set on the accelerating and decelerating means 31 td=FH/f×t.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for preventing free running of a motor at the time of an instantaneous power failure or a power failure.

[0002]

FIG. 12 shows the configuration of a conventional general inverter device. Referring to FIG. 1, an inverter device 1 includes an inverter circuit 2 including a rectifier circuit 4 and an inverter main circuit 5, and a control means 3 for controlling the inverter circuit 2. The output frequency f is determined according to the given operation command ST and speed command value FC, and PW
The M control circuit 7 obtains a sine-wave-shaped PWM signal and drives the motor 11 connected to the inverter main circuit 5 at a variable speed.

The voltage detecting means 8 in the control circuit 3
In this embodiment, the output voltage of the rectifier circuit 4 (hereinafter, referred to as DC voltage VPN) is constantly detected, and the detected DC voltage VPN is output to the outside as a DC voltage value PN. When the voltage drops to a certain voltage (insufficient voltage), a contact 9 provided between the acceleration / deceleration means 6 and the PWM control circuit 7 is opened as undervoltage protection. As a result, if undervoltage protection works, PWM
The PWM signal from the control circuit 7 stops, and the motor 11 enters a free-run state. Thereafter, the motor 11 decelerates to a stop depending on the state of the motor load. Therefore, when an abnormality such as a momentary power failure or power failure occurs in the input AC power supply 12, the motor 11
Cannot be controlled, and it is difficult to reliably stop the motor 11 within a certain time.

On the other hand, by using a plurality of such inverter devices 1 in a spinning device or the like, a proportional control for maintaining the speed ratio of the plurality of motors 11 connected to these inverter devices 1 at a constant ratio corresponding to the load. When configuring the operation system, the input AC power supply 12
During normal operation without momentary power failure or power failure, the speed command value F having a constant speed ratio for each inverter device 1
By giving C, each motor 11 can be operated in proportional control.

However, when an instantaneous power failure or power failure occurs in the AC power supply 12 and the DC voltage VPN of each inverter device 1 becomes an undervoltage, the undervoltage protection functions as described above and the inverter device 1 is connected to the inverter device 1. The motor 11 enters a free-run state. At this time, each inverter device 1 or each motor 11 takes time until the DC voltage VPN reaches the undervoltage due to a difference in the capacity of the smoothing capacitor 10 connected to the output of the rectifier circuit 4 or the inertia of the motor load, or The time to stop in the free run state is different. Accordingly, there is a problem that the speed ratio at the time of the instantaneous power failure or power failure cannot be maintained until each motor 11 decelerates and stops after the instantaneous power failure or power failure occurs in the AC power supply 12.

In this case, the instantaneous power failure non-stop operation function (a function of decelerating before reaching an undervoltage and continuing the operation by the regenerative electric power from the motor 11) which may be provided in the inverter device 1 is used. Although the operation of each of the inverter devices 1 can be continued, this function is not synchronized between the inverter devices, and the deceleration rate also depends on the capacity of the smoothing capacitor 10 and the inertia of the motor load. Proportional control operation cannot be maintained.

[0007] In view of the above, for example, Japanese Unexamined Patent Publication No. 2-221424 addresses the above-mentioned problem by configuring a system as shown in FIG. That is, in FIG. 13, the inverter devices 1a to 1c to which the spindle driving or peripheral device driving motors 11a to 11c are connected, respectively, are connected as input power via the undervoltage detecting means 13 functioning as a power failure detector. Common AC power supply 1
2 are connected, and as commands, operation commands ST1 to ST3 output from the external control means 14 backed up by the uninterruptible power supply 15 and speed command values FC1 to FC
3 is input. Further, the external control means 14 feeds back the DC voltage values PN1 to PN3 from the respective inverter devices 1a to 1c, and receives an undervoltage signal UV from the undervoltage detection means 13. In the above publication, the rectifier circuit 4 and the smoothing capacitor 10 included in the inverter devices 1a to 1c are separated, and are shared as one converter.

When the AC power supply 12 receives an undervoltage signal UV from the undervoltage detection means 13 during a momentary power failure or power failure, the external control means 14
Based on the DC voltage values PN1 to PN3 from a to 1c,
A speed command value F for reducing the DC voltage values PN1 to PN3 without causing an undervoltage and maintaining a speed ratio.
C1 to FC3 are output to each of the inverter devices 1a to 1c, and each of the inverter devices 1a to 1c obtains regenerative electric power by deceleration to continue the operation.

However, in the case of the above configuration, the uninterruptible power supply 15 is required for the external control means 14, so that the cost of the entire system is increased and an extra installation space is occupied. Further, the external control means 14 controls the speed command value FC for deceleration based on the DC voltage values PN1 to PN3 from the inverter devices 1a to 1c and a fixed deceleration stop time.
Since the calculation of 1 to FC3 is required, the function is complicated, and the control accuracy is deteriorated due to a calculation delay or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent a free-run state of a motor by using a low-cost and easy configuration when a momentary power failure or power failure occurs. An object of the present invention is to provide an inverter device capable of decelerating and stopping in time.

[0011]

In order to achieve the above object, an inverter device according to the present invention comprises an inverter circuit for driving a motor and control means for controlling the inverter circuit, wherein the control means comprises: When the undervoltage signal indicating the decrease of the input voltage or the DC voltage generated in the inverter circuit is not input, the motor is operated according to the operation command and the speed command value given from the external control means, and the undervoltage signal is input. In this case, the motor has a deceleration function for decelerating and stopping the motor for a fixed time regardless of the operation command and the speed command value (claim 1).

With this configuration, when a momentary power failure or power failure occurs in the input power supply of the inverter circuit, the operation command and the speed command value from the outside are cut off in response to the undervoltage signal, and the deceleration provided by the control means is controlled. Since the motor is decelerated and stopped in a certain time by the function, regenerative power of the motor returning to the inverter device is obtained by the deceleration, and the motor control can be continued until the motor is stopped.

Further, the control means has timer means for starting a timed operation when the undervoltage signal is input. When the undervoltage signal is no longer input during the timed operation of the timer means, the motor is decelerated and decelerated. The suspension is stopped (claim 2). With such a configuration, even during a deceleration due to an instantaneous power failure or a power failure, the deceleration is stopped if the power is restored while the timer means is operating in a timed manner. The operation can be continued without stopping the motor.

Further, when the undervoltage signal is not inputted when the motor is stopped when the undervoltage signal is inputted, the control means controls the motor for a predetermined time until the speed command value given from the external control means. An acceleration function for accelerating is provided (claim 3). With such a configuration, in the case where the power is restored during a deceleration stop due to an instantaneous power failure or a power failure, after the motor stops, the motor is accelerated again to a speed command value given from the external control means in a fixed time. Automatic restart is possible.

In these cases, the control means controls the motor so that the acceleration or deceleration pattern is a polygonal line or a curved line. With such a configuration, the acceleration / deceleration speed pattern is a polygonal line or a curved line, so that an acceleration rate or a deceleration rate can be set in accordance with the speed. And the power can be used effectively.

In addition, when the external trigger signal is not input, the control means operates the motor in accordance with the operation command and the speed command value given from the external control means. When the external trigger signal is input, the control means operates the motor and the speed command. A deceleration function is provided for decelerating and stopping the motor for a fixed time regardless of the value (claim 5). With such a configuration, the motor is decelerated and stopped within a predetermined time when the external trigger signal is input, so that, for example, when the emergency stop signal is used as the external trigger signal, the motor can be stopped safely and reliably.

In the above means, the power supply voltage of the external control means is provided from the DC voltage generated in the inverter circuit. With this configuration, when a momentary power failure or power failure occurs, the regenerative power of the motor that returns to the inverter circuit by decelerating the motor can be supplied to the external control means.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the inverter device of the present invention is used for proportional control of a motor will be described below with reference to FIGS.

First, in FIG. 1 showing the electrical configuration of the inverter device, an inverter device 21 includes a rectifier circuit 24 formed by connecting diodes and the like in a three-phase bridge, and a positive DC power supply line as an output line of the rectifier circuit 24. 25 and a smoothing capacitor 27 connected between the negative DC power supply line 26 and
The inverter circuit 22 includes an inverter main circuit 28 in which switching elements such as GBTs are connected in a three-phase bridge, and control means 23 for controlling the inverter circuit 22 includes, for example, a microcomputer. A three-phase AC power supply 37 is connected to an input terminal of the rectifier circuit 24, and a motor 36 such as an induction motor is connected to an output terminal of the inverter main circuit 28.

In the control means 23, an operation command ST and a speed command value F given from outside the inverter device 21 are provided.
C is input to the acceleration / deceleration means 31 via the contacts 29 and 30 formed of hardware or software, respectively. The contacts 29 and 30 are connected to a constant-time deceleration unit 3 described later.
It is opened and closed by instructions from 5.

In a normal operation in which no instantaneous power failure or power failure occurs, the acceleration / deceleration means 31 receives an output from the current output frequency f (0 when stopped) and externally receives an operation command ST indicating operation start. The output frequency f is determined within a range of a predetermined acceleration / deceleration ratio so as to follow a given speed command value FC. This acceleration / deceleration ratio is
6 is defined as the time required to reach the maximum frequency FH from the stop state or the time required to stop from the maximum frequency FH, and is hereinafter generally referred to as acceleration / deceleration time tc. That is, the speed command value FC provided from the outside
Is greater than the change rate determined by the normal acceleration / deceleration time tc, the output frequency f limited by the change rate determined by the normal acceleration / deceleration time tc is output.
When the rate of change of the externally applied speed command value FC is smaller than the rate of change determined by the normal acceleration / deceleration time tc, the speed command value FC is output as it is as the output frequency f. When an instantaneous power failure or power failure occurs, the normal acceleration / deceleration time in the acceleration / deceleration means 31 is replaced by a deceleration rate (deceleration time td described later) provided from the fixed-time deceleration means 35, and thereafter, the replaced deceleration rate , The output frequency f for deceleration is determined.

The output frequency f is input to the PWM control circuit 33 via a contact 32 constituted by hardware or software. This contact 32 is provided for protecting an undervoltage in a general inverter device as described above, and in this embodiment, particularly when the motor 36 needs to be set to a free-run state. It is always closed except for.

The PWM control circuit 33 performs pulse width modulation by, for example, a sine wave-triangle wave comparison method based on V / f constant control, and generates a three-phase sine wave PWM signal having the same frequency as the output frequency f. The PWM signal is output to each gate of the switching element constituting the inverter main circuit 28. Thereby, the inverter main circuit 28
The motor 36 connected to the output terminal is driven to rotate.

The voltage detecting means 34 has a function of detecting the DC voltage VPN of the DC power supply section, which is the output of the rectifier circuit 24. The voltage detecting means 34 is used to protect the DC voltage VPN from overvoltage and uses the DC voltage VPN. It is used when detecting a momentary power failure or power failure.

The constant-time deceleration means 35 closes the contacts 29 and 30 during normal operation. Further, the instruction of the deceleration rate (deceleration time td) is not output to the acceleration / deceleration means 31.
On the other hand, an AC power supply 37 as an input power supply of the inverter device 21
Undervoltage signal UV indicating that a momentary or power failure has occurred
Is input, the contacts 29 and 30 are opened and the operation command S
T and the speed command value FC are invalidated, and based on the output frequency f when the undervoltage signal UV is input, a deceleration rate (deceleration rate) for decelerating and stopping the motor 36 for a fixed time (constant deceleration time t) ( The deceleration time td) is calculated, and the acceleration / deceleration means 3
1 is instructed.

FIG. 2 shows the inverter device 21 (2
The configuration of a system that uses a plurality of motors 1a to 21c) and performs a proportional control operation of a plurality of motors 36 (36a to 36c) connected thereto is shown.

The inverter devices 21a to 21c to which the motors 36a to 36c are respectively connected are connected to a three-phase AC power supply 37 via an undervoltage detection means 38 as an input power supply. The under-voltage detecting means 38 includes an AC power supply 37.
When the AC voltage falls below a preset lower limit voltage value, an undervoltage signal UV is generated (ON), and when the AC voltage rises above a preset upper limit voltage value, the undervoltage signal UV is stopped (OFF) (has a hysteresis characteristic). And outputs the undervoltage signal UV to each of the inverter devices 21a to 21c.

External control means 39 provided in common to each of the inverter devices 21a to 21c outputs operation commands ST1 to ST3 and speed command values FC1 to FC3 to each of the inverter devices 21a to 21c, and performs normal operation. It controls the entire system at the time. The external control means 39 is directly supplied with power from the AC power supply 37.

Next, the operation of this embodiment will be described with reference to FIG. It should be noted that the proportional control referred to here means that each motor 3
The speed ratios 6a to 36c are not always constant and can be changed according to the speed command values FC1 to FC3 given according to the state of the load. This refers to the retained control.

FIG. 3 shows changes in the output frequencies f1 to f3 and the speed command values FC1 to FC3 of the inverter devices 21a to 21c when the motors 36a to 36c are proportionally controlled, and the timings of the operation signal ST and the undervoltage signal UV. The chart is shown.

When the undervoltage signal UV from the undervoltage detection means 38 is not input, each of the inverter devices 21a to 21c has the contacts 29 and 30 shown in FIG. Run command ST given
1 to ST3 and speed command values FC1 to FC3
1 is input. Then, the acceleration / deceleration means 31 drives the motors 36a to 36c at the output frequency f according to the commands.

In such a normal operation state in which the undervoltage signal UV is OFF, at time t1 shown in FIG. 3, operation signals ST1 to ST3 for instructing the inverter devices 21a to 21c to start operation are given from the external control means 39. When turned on, the inverter devices 21a to 21c start accelerating according to the speed command values FC1 to FC3, respectively, and after time t2, operate at a constant speed according to the command. The speed command values FC1 to FC3 have a constant frequency ratio, for example, FC1: FC2: FC3 = at the time of the acceleration operation command from time t1 to time t2 and at the time of the constant speed operation command after time t2.
It is set to be 60 Hz: 50 Hz: 40 Hz.

Now, at the time t during such a proportional control operation,
In 3, when the short-circuit or power failure occurs in the AC power supply 37 and the undervoltage signal UV is turned on, each of the inverter devices 21a
21c, the constant-time deceleration means 35 simultaneously
30 to release the operation command ST and the speed command value FC from the acceleration / deceleration means 31,
A deceleration ratio (deceleration time td) for linearly decelerating and stopping at a constant time from the output frequency f of 1 is calculated, and the acceleration / deceleration means 31 is commanded. Then, the acceleration / deceleration means 31 replaces the normal acceleration / deceleration time tc during the normal operation with the deceleration rate (deceleration time td), and thereafter decelerates according to the deceleration rate.

The deceleration time td indicating the deceleration rate is defined as the time required for the motor 36 operating at the highest frequency FH to stop, similarly to the normal acceleration / deceleration time tc, and the undervoltage signal UV changes from OFF to ON. Using the output frequency f at the time of change (current output frequency f) and the constant deceleration time t (t shown in FIG. 3), which is the time required to stop thereafter, it is calculated as in equation (1). Note that the normal acceleration / deceleration time t
c, the maximum frequency FH, and the constant deceleration time t are preset in the inverter devices 21a to 21c as parameters. Deceleration time td = maximum frequency FH / current output frequency f × constant deceleration time t (1)

That is, when the current output frequency f is high, the deceleration time td is set to be small in inverse proportion to the current output frequency f (that is, the deceleration ratio is large). Conversely, when the current output frequency f is low, the deceleration time td is increased ( That is, the deceleration rate is set to be small), so that the deceleration is stopped at the constant deceleration time t irrespective of the current output frequency f. As described above, at the time t3 in FIG. 3, the deceleration time td calculated by the equation (1) based on the current output frequency f is calculated by using the inverter devices 21a to 21c.
At the same time, the motors 36a to 36c can be stopped at the constant deceleration time t while maintaining the speed ratio regardless of the value of the output frequency f of each of the inverter devices 21a to 21c at that time. it can.

As described above, according to the first embodiment, when an instantaneous power failure or a power failure occurs in the AC power supply 37, which is the input power supply of the inverter circuit 21, the constant-time deceleration means 35 supplies the externally supplied undervoltage. In response to the signal UV, the operation command ST and the speed command value FC from outside are cut off, and the deceleration time td is commanded to the acceleration / deceleration means 31 to linearly decelerate and stop the motor 36 for a fixed time. Obtains regenerative electric power which is regenerated from the motor 36 to the DC power supply through the inverter main circuit 28 by the deceleration,
Motor control can be continued until stopping. Further, since the motor 36 does not enter the free-run state, the motor 36 can be stopped reliably at the scheduled time. Further, a plurality of inverter devices 21a
Even when the proportional control operation is performed using the motors 21 to 21c, the speed can be reduced while maintaining the speed ratio of the motors 36a to 36c, and these can be stopped at the same time.

Next, a second embodiment of the present invention will be described with reference to FIGS. In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Only different components will be described.

In FIG. 4 showing the electrical configuration of the inverter device, a timer means 40 outputs an undervoltage signal UV
In the case of F, no function is performed. However, when an instantaneous power failure or a power failure occurs in the AC power supply 37 for the inverter device 21 and the undervoltage signal UV changes from OFF to ON, in synchronization with this, a predetermined period of time previously set as a parameter is synchronized. Start timer operation. Then, the power is restored before the timer operation is completed, and when the undervoltage signal UV changes from OFF to ON, the contact 2 opened by the constant time deceleration means 35
It functions to close 9, 30.

Next, FIG.
The operation when the proportional control system shown in FIG. 1 is configured will be described with reference to FIG. Note that time t1 in FIG.
Since the operation from time t3 to time t3 is the same as that of FIG. 3 based on the first embodiment described above, the operation after time t3 will be described below.

At time t3, when an instantaneous power failure or power failure occurs in the AC power supply 37 and the undervoltage signal UV is turned on, the constant-time deceleration means 35 of each of the inverter devices 21a to 21c operates.
Open the contacts 29 and 30 to open the operation command ST and the speed command value F.
Deceleration time t for shutting down C and decelerating to a stop
d to the acceleration / deceleration means 31. Thereby, the motor 36a connected to each of the inverter devices 21a to 21c
36c starts deceleration while keeping the speed in a proportional relationship. At the same time, the timer means 40 starts the timer operation.

When the AC power supply 37 is restored at time t4 before the timer operation of the timer means 40 is completed,
The timer means 40 closes the contacts 29, 30 opened by the fixed time deceleration means 35. Thus, the output frequency f of each of the inverter devices 21a to 21c becomes equal to the speed command values FC1 to FC given from the external control means 39 after time t4.
In order to follow C3, the motor 36a-36c is operated at a constant speed in accordance with the command after time t5 when the command value is followed by increasing the deceleration ratio (deceleration time td) in accordance with the acceleration ratio that differs only in sign. Between the time t4 and the time t5, the motors 36a to 36c keep the speed in a proportional relation.

Thereafter, when a power failure occurs at time t6, each of the inverter devices 21a to 21c starts decelerating similarly to the case at time t3, and the timer means 40 starts the timer operation. Then, since the undervoltage signal UV does not return to OFF until time t7 when the timer operation is completed, each of the inverter devices 21a to 21c continues to decelerate until it stops (time t8).

As described above, according to the second embodiment,
In addition to the effects of the first embodiment described above, even during a deceleration due to an instantaneous power failure or a power failure, if the power is restored while the timer means 40 is operating as a timer, the deceleration is stopped and the external control means 39 Since the operation returns to the operation in accordance with the given speed command value FC, it has a function of determining a temporary power failure shorter than the timer time as an instantaneous interruption, and operates without stopping the motor 36 for an instantaneous interruption. Can continue.

Next, a third embodiment of the present invention will be described with reference to FIGS. In FIG. 6, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. Only different components will be described.

In FIG. 6 showing the electrical configuration of the inverter device, a constant-time acceleration / deceleration means 41 has a deceleration function for decelerating and stopping the motor 36 when the undervoltage signal UV changes from OFF to ON. If the undervoltage signal UV is OFF when the vehicle stops due to deceleration, the vehicle has an acceleration function to start acceleration to return to operation according to the external operation command ST and the speed command value FC. That is,
If the AC power supply 37 is restored and the undervoltage signal UV is OFF when the AC power supply 37 is stopped due to a power failure, the contacts 29 and 30 are closed and an external operation command ST is issued.
And the speed command value FC are input to the acceleration / deceleration means 31, and the acceleration ratio (acceleration time ta) capable of accelerating from the stop to the speed command value FC in a fixed time is determined by the acceleration / deceleration means 3.
Command 1

Next, referring to FIG.
The operation when the proportional control system shown in FIG. 1 is configured will be described with reference to FIG. Note that time t1 in FIG.
Since the operation from time t7 to time t7 is the same as that of FIG. 5 based on the above-described second embodiment, the operation after time t7 will be described below.

After the occurrence of the power failure at time t6, the undervoltage signal UV does not return to OFF until the time t7 when the timer operation of the timer means 40 is completed, so that the inverter devices 21a to 21c continue to decelerate until they stop. . At time t8 between time t7 and stop time t9, the AC power supply 37 recovers power and the undervoltage signal UV changes from ON to OFF.
When the output frequency of the inverter devices 21a to 21c becomes 0 Hz and the motors 36a to 36c stop at time t9, the constant time acceleration / deceleration means 41 outputs the undervoltage signal U
When V is in the OFF state, the contacts 29 and 30 are closed, and the operation command ST and the speed command value FC from the external controller 39 are input to the acceleration / deceleration means 31. Further, the acceleration ratio (acceleration time ta) at which the vehicle can be accelerated from the stop to the speed command values FC1 to FC3 in a certain time (constant acceleration time t) previously set as a parameter is commanded to the acceleration / deceleration means 31. The deceleration rate (deceleration time td) is replaced with this acceleration rate (acceleration time ta).

The acceleration time ta indicating the acceleration ratio is defined as the time required for the stopped motor 36 to reach the maximum frequency FH. Like the equation (1), the speed command value FC, the maximum frequency FH, Based on the constant acceleration time t, which is the time from when the vehicle stops to when the speed command value FC is reached, the calculation is performed as in equation (2). Acceleration time ta = maximum frequency FH / speed command value FC × constant acceleration time t (2)

As described above, according to the third embodiment, in addition to the deceleration function, the speed given from the external control means 39 when the undervoltage signal UV is not input when the motor is stopped due to an instantaneous power failure or power failure. A constant-time acceleration / deceleration means 41 having an acceleration function for accelerating to a command value FC in a constant time is provided. Therefore, when the power is restored during the deceleration due to the momentary power failure or the power failure, the external control unit 3 is stopped again after the motor 36 stops.
Since the vehicle is accelerated in a certain time until the speed command value FC given from step 9 is reached, in addition to the effects of the above-described second embodiment, an automatic restart at the time of power recovery is possible. Also,
Even when a plurality of inverter devices 21a to 21c are used, the acceleration can be performed while maintaining a constant speed ratio, so that the proportional control operation can be performed.

The restart after the stop is performed at the stop time t in order to wait for the return of the undervoltage signal UV due to the power recovery.
It may be after waiting for a certain time from 9. in this case,
The power of the external control means 39 may not be maintained within the elapsed time, and the speed command values FC1 to FC3 may be reset. The operation is performed according to the speed command values FC1 to FC3 having the speed ratio of. Further, the above-mentioned constant acceleration time does not need to be the same as the constant deceleration time which is the time until a stop at the time of a momentary power failure or a power failure. Should be set to.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. In FIG. 8, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. Only different components will be described.

In FIG. 8 showing the electrical configuration of the inverter device, the constant time deceleration means 42 closes the contacts 29 and 30 during normal operation, and opens the contacts 29 and 30 when the undervoltage signal UV is input. To invalidate the speed command value FC and the operation command ST. Then, when a recalculation request signal RQ is given from a recalculation request unit 43 to be described later, one or two or more constant deceleration times (tDEC1, tDEC2, tDEC3 shown in FIG. 9) previously provided as parameters are calculated based on the equation (1). The deceleration time td calculated in this way is sequentially instructed to the acceleration / deceleration means 31.

The recalculation request means 43 outputs the undervoltage signal UV
Is input, a recalculation request signal RQ is output to the constant time deceleration means 42 at time intervals (tM1 and tM2 in FIG. 9) which are previously set as parameters. This recalculation request signal RQ instructs the fixed-time deceleration means 42 at a timing when the deceleration rate (deceleration time td) should be reset during deceleration due to a momentary power failure or power failure.

Now, referring to FIG.
The operation when the proportional control system shown in FIG. 1 is configured will be described with reference to FIG. The time t1 in FIG.
Since the operation from time t3 to time t3 is the same as that of FIG. 3 based on the first embodiment described above, the operation after time t3 will be described below.

At time t3, when an instantaneous power failure or power failure occurs in the AC power supply 37 and the undervoltage signal UV is turned on, the constant time deceleration means 42 of each of the inverter devices 21a to 21c opens the contacts 29 and 30 to execute the operation command ST1. To ST3 and the speed command values FC1 to FC3. Then, the recalculation request means 43 sends a recalculation request signal R to the fixed time deceleration means 42.
Output Q. The constant time deceleration means 42 to which the recalculation request signal RQ has been input decelerates the deceleration time td calculated based on the equation (1) from the first constant deceleration time tDEC1 for deceleration and stop to the acceleration / deceleration means 31. Command. This allows
Each of the inverter devices 21a to 21c simultaneously replaces the normal acceleration / deceleration time tc of the acceleration / deceleration means 31 with the above-mentioned deceleration time td.
While maintaining the speed ratio at time t3, time t8 (=
At (t3 + tDEC1), deceleration is started with a slope that stops.

At time t4 when the time tM1 as a parameter has elapsed from time t3, the undervoltage signal U
Since V remains ON, the inverter devices 21a to 21a-2
Each recalculation requesting means 43 outputs the next recalculation requesting signal RQ to the constant time deceleration means 42 in FIG. As a result, the constant time deceleration means 42 instructs the acceleration / deceleration means 31 from the second constant deceleration time tDEC2 for decelerating and stopping based on the equation (1) to the acceleration / deceleration means 31 so that each motor 36a
36c continue deceleration with an inclination such that they stop at time t7 (= t4 + tDEC2) while maintaining the speed ratio at time t4.

Similarly, at time t5 when the time tM2 as a parameter has elapsed from time t4, the undervoltage signal UV is still ON, so that the recalculation request means 43 outputs the next recalculation request signal RQ. I do. Then, the constant time deceleration means 42 instructs the acceleration / deceleration means 31 from the third constant deceleration time tDEC3 for deceleration and stop based on the equation (1) to the acceleration / deceleration means 31.
-36c continue deceleration while maintaining the speed ratio at time t5, and stop at time t6 (= t5 + tDEC3).

Accordingly, in the case of the present embodiment, the constant deceleration time t from the start of deceleration to the stop is given by the following equation (3). In this case, as shown in FIG. 9, the speed deceleration pattern is set such that the constant deceleration time increases as the rotation speed increases, and the rate of change in deceleration decreases. Constant deceleration time t = tM1 + tM2 + tDEC3 (3)

Next, the reason why the deceleration pattern is formed in such a broken line will be described. The kinetic energy W of the rotating machine is calculated by the following equation (4). W = (1/2) × J × ω ² [J] (4) where ω = 2π × (n / 60) [rad / s] n: rotation speed [rpm] J: moment of inertia [kgm ² ]

That is, the kinetic energy W is equal to the rotation speed 2
Since it is proportional to the power, if you decelerate at a constant deceleration rate,
As the rotation speed increases, the energy regenerated from the motor 36 to the inverter device 21 increases, and as a result, the DC voltage VPN tends to be overvoltage during high-speed rotation, while it tends to be undervoltage during low-speed rotation. Further, for the purpose of protection against overvoltage, the regenerative energy is wastefully consumed by the power generation braking unit or the like. Therefore, if the constant deceleration time is switched to a plurality of stages according to the rotation speed, the deceleration rate can be set to increase as the rotation speed decreases, and the regenerative energy can be used efficiently.

As described above, according to the fourth embodiment, the constant time deceleration means 42 responds to the recalculation request signal RQ output from the recalculation request means 43 every predetermined time.
The deceleration rate (deceleration time td) based on the constant deceleration time previously provided as a parameter is calculated and instructed to the acceleration / deceleration means 31. Can be set to Therefore, the regenerative energy at the time of deceleration proportional to the square of the rotation speed can be controlled, and the regenerative energy can be used effectively without generating overvoltage or undervoltage.

The set number of times (the number of polygonal lines) is 2
The number of times may be four or four or more times, and a deceleration rate that becomes a curve may be set. Further, as the recalculation request signal RQ, a trigger signal which is started in synchronization with the undervoltage signal UV and has a fixed time interval may be used. Further, the same can be applied to a pattern during acceleration.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 10, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. Only different components will be described.

In FIG. 10 showing the configuration of a system for performing proportional control operation of a plurality of motors, external signal output means 44
Generates a trigger signal TRG such as an emergency stop signal and outputs the trigger signal TRG to the inverter devices 21a to 21c having the configuration shown in FIG. This trigger signal TRG is supplied to the undervoltage detecting means 38 shown in FIG.
Motors 36a-36 connected to the inverter devices 21a-21c instead of the undervoltage signal UV output from the
c is decelerated and stopped for a fixed time. Each inverter device 21
This deceleration stop operation in a to 21c is described in the first section.
This is the same as the deceleration stop operation described in the embodiment.

Inverter device 2 having the structure shown in FIG.
According to the above-described system using No. 1, the motor 36 can be decelerated and stopped in a fixed time according to the trigger signal TRG output from the external signal output means 44 in response to a request for an emergency stop or the like. Effects can be obtained. In addition, since the deceleration stop can be reliably performed in a fixed time, a function corresponding to the trigger signal TRG in the external control means 39 or the like, for example, an emergency stop function can be eliminated.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 11, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. Only different components will be described.

In FIG. 11, which shows the configuration of a system for performing proportional control operation of a plurality of motors, external control means 39 is provided with a positive DC power supply line 25 of inverter circuit 22 of inverter device 21 (21c) having the configuration shown in FIG. And the negative side DC power supply line 26, and is supplied with power from the DC voltage VPN.

When an instantaneous power failure or power failure occurs in the AC power supply 37, each of the inverter devices 21a to 21c can obtain regenerative energy by decelerating the motors 36a to 36c connected thereto. Therefore, according to the above configuration, the power source of the external control means 39 is connected to any of the inverter devices 21.
By supplying power from the DC power supply units a to 21c, the power of the external control unit 39 can be maintained by regenerative energy even at the time of a momentary power failure or power failure.

As described above, according to the present embodiment, even when a momentary power failure or power failure occurs, external power can be supplied without using an uninterruptible power supply by using the power regenerated in the inverter device 21 by the deceleration of the motor 36. The power supply of the control means 39 can be maintained, and the reset of the operation command ST and the speed command value FC can be prevented. In addition, the inverter devices 21a to 21c
By connecting the positive DC power supply line 25 and the negative DC power supply line 26 to each other, the external control means 39 can be further stabilized.
Power can be maintained.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. The undervoltage detection means 38 for detecting a momentary power failure or power failure may be incorporated in the input portion of the rectifier circuit 24 of the inverter device 21. Further, the voltage detection means 34 of the inverter device 21 may detect a momentary power failure or a power failure.
In these cases, when performing control requiring synchronization such as proportional control using a plurality of inverter devices 21, a momentary power failure or power failure is detected in any one of the inverter devices 21, and the signal is transmitted to another inverter device 21. Is configured to be transmitted.

When rapid deceleration is required, an overvoltage of the DC voltage VPN due to regenerative electric power is prevented by providing the inverter device 21 with a dynamic braking unit combining a resistor and an electrical or mechanical contact. be able to.

[0072]

Since the present invention is as described above,
The following effects are obtained. According to the inverter device of the first aspect, when the input voltage of the inverter circuit or the undervoltage signal indicating the decrease of the DC voltage in the inverter circuit is not input, the operation is performed according to the operation command and the speed command value given from the external control means, Since the motor has a deceleration function that decelerates and stops the motor for a certain period of time when the undervoltage signal is input, even if an instantaneous power failure or power failure occurs, the regenerative power of the motor that returns to the inverter device by deceleration is obtained, Motor control can be continued for a while, and the motor can be reliably stopped at a predetermined time.

According to the inverter device of the second aspect,
Timer means for starting operation when an undervoltage signal is input is provided.When the undervoltage signal is no longer input during operation of this timer means, motor deceleration and stop are stopped. Even
If the power is restored while the timer means is operating, the operation can be continued without stopping the motor.

According to the inverter device of the third aspect,
If an undervoltage signal is not input when stopped due to an undervoltage signal, an acceleration function that accelerates to a speed command value given from external control means in a fixed time is provided, so automatic restart at power recovery Becomes possible.

According to the inverter device of the fourth aspect,
Since the motor is controlled so that the acceleration or deceleration pattern becomes a broken line or a curved line, the regenerative electric power can be effectively used, and an undervoltage or an overvoltage of the DC voltage portion can be prevented.

According to the inverter device of the fifth aspect,
Since the motor is decelerated and stopped by an external trigger signal instead of the undervoltage signal, the motor can be safely and reliably stopped within a certain period of time, for example, when the emergency stop signal is used as the external trigger signal. Further, the function corresponding to the external trigger signal in the external control means or the like can be made unnecessary.

According to the inverter device of the sixth aspect,
Since the power supply voltage of the external control means is provided from the DC voltage generated in the inverter circuit, the power supply of the external control means can be maintained even when a momentary power failure or power failure occurs.

[Brief description of the drawings]

FIG. 1 is an electrical configuration diagram of an inverter device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a proportional control system using a plurality of inverter devices.

FIG. 3 is a diagram showing changes in an output frequency and a speed command value, and timings of an operation signal ST and an undervoltage signal UV.

FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 5 is a diagram showing changes in an output frequency and a speed command value, and a timing of an operation signal ST, an undervoltage signal UV, and a timer operation.

FIG. 6 is a view corresponding to FIG. 1, showing a third embodiment of the present invention.

FIG. 7 is a diagram corresponding to FIG. 5;

FIG. 8 is a view corresponding to FIG. 1, showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a change in output frequency and timings of an operation signal ST, an undervoltage signal UV, and a recalculation request signal RQ.

FIG. 10 is a view corresponding to FIG. 2, showing a fifth embodiment of the present invention;

FIG. 11 is a view corresponding to FIG. 2, showing a sixth embodiment of the present invention;

FIG. 12 is a diagram corresponding to FIG. 1 showing a conventional example.

FIG. 13 is a diagram corresponding to FIG. 2 showing a conventional example.

[Explanation of symbols]

1, 1a-1c, 21, 21a-21c are inverter devices, 2, 22 are inverter circuits, 3, 23 are control means,
6, 31 are acceleration / deceleration means, 7, 33 are PWM control circuits,
8, 34 are voltage detecting means, 11, 11a to 11c, 3
6, 36a to 36c are motors, 13 and 38 are undervoltage detecting means, 14 and 39 are external control means, 35 and 42 are fixed-time deceleration means, 40 is timer means, 41 is fixed-time acceleration / deceleration means, and 43 is Calculation request means 44 is an external signal output means.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Minami 2121 Asahi-machi, Mie-gun, Mie Prefecture 2121 Nagoya, Toshiba Mie Plant (72) Inventor Kazuharu Ohashi 2121, Asahi-machi, Mie-gun, Mie Prefecture Address Co., Ltd.Toshiba Mie Plant

Claims (6)

[Claims] 1. An inverter circuit for driving a motor, and control means for controlling the inverter circuit, wherein the control means has a deficiency indicating a drop in an input voltage of the inverter circuit or a DC voltage generated in the inverter circuit. When the voltage signal is not input, the motor is operated in accordance with the operation command and the speed command value given from the external control means.When the undervoltage signal is input, the motor is operated for a fixed time regardless of the operation command and the speed command value. An inverter device having a deceleration function for decelerating and stopping. The control means includes timer means for starting a timed operation when an undervoltage signal is input. When the undervoltage signal is no longer input during the timed operation of the timer means, the control means decelerates the motor. The inverter device according to claim 1, wherein the stop is stopped. 3. The control means, if the undervoltage signal is not input when the motor is stopped when the undervoltage signal is input, controls the motor for a fixed time until a speed command value given from the external control means. 3. The inverter device according to claim 1, further comprising an acceleration function for accelerating. 4. The inverter device according to claim 1, wherein the control unit controls the motor so that the acceleration or deceleration pattern is a polygonal line or a curved line. 5. An inverter circuit for driving a motor, and control means for controlling the inverter circuit, wherein the control means, when an external trigger signal is not inputted, according to an operation command and a speed command value given from an external control means. An inverter device having a deceleration function for operating a motor and decelerating and stopping the motor for a predetermined time when the external trigger signal is input, regardless of the operation command and the speed command value. 6. The inverter device according to claim 1, wherein a power supply voltage of the external control means is provided from a DC voltage generated in the inverter circuit.