JPH02261090A - Motor lock detector - Google Patents

Abstract

PURPOSE:To judge a lock accurately to prevent a malfunction by judging a motor to be locked; when a state, where the current command value or current detected value of a motor is not within the range of a specified reference value, continues for more than a specified period of time. CONSTITUTION:A comparing circuit 13 compares an inputted motor current command value or detected motor current with positive and negative reference value generator circuits 11 and 12. When a positive reference value or more or a negative reference value and less is detected, the out-of-tolerance signal of a motor current signal is outputted and inputted to one terminal of an AND circuit 15 and a delay circuit 14. When the output of said comparing circuit 13 continues for more than a delay time of said delay circuit 14, the signal is outputted to the other terminal of said AND circuit 15, which circuit 15 outputs an out-of-tolerance signal. Thus, a motor lock is detected accurately and a malfunction is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motor lock detection device used in a motor control system to detect a locked state of a motor.

[Conventional technology] Electric i 1! In the I control system, the locked state of the electric motor has conventionally been detected as follows.

(1) The current value of the motor is detected, and if this detected current value exceeds a certain set value, it is determined that the motor is locked.

(2) The operating speed of the electric motor is detected, and if this detected speed becomes less than a certain set value and this state continues for a predetermined time or more, it is determined that the electric motor is locked.

[Problems to be Solved by the Invention] However, when starting, stopping, or reversing the rotation direction of a motor, for example, a current larger than the rated current flows through the motor. With a lock type one-fold means that locks the motor when the detected current value exceeds a certain set value, it is easy to make an erroneous judgment at the time of starting and stopping one reversal, and it is difficult to accurately judge whether the motor is locked.

In addition, when driving an electric motor, low-speed operation may be performed continuously, so the lock determination means that locks the electric motor when the detected speed value is below the set value for more than a predetermined period of time as described in (2) above is not suitable. When performing the above-mentioned continuous low-speed operation, the set value must be changed as necessary.

The present invention has been developed in view of the above problems, and it is possible to accurately detect the locked state of the motor without making an erroneous judgment when starting, stopping, or reversing the motor, and without changing the setting value for low speed detection. It is an object of the present invention to provide a motor lock detection device that enables this.

[Means and effects for solving the problem, that is, the motor lock detection device according to the present invention includes reference value deviation detection means for detecting that the current command value or current detection value of the motor deviates from a predetermined reference value; The device further includes lock determining means that determines that the motor is locked when the U level deviation detection state by the reference value deviation detecting means continues for a predetermined period of time or more.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows its configuration. In the figure, reference numeral 11 denotes a positive reference generation circuit, and this positive reference generation circuit 11 generates a positive reference value and outputs it to the comparison circuit 13. Further, 12 is a negative reference generation circuit, and this negative reference generation circuit 12 generates a negative reference value and outputs it to the comparison circuit 13. The above comparison circuit 13
compares the current command value or current detection value of the motor with the above positive reference value and negative reference value. If the motor current signal is outside the allowable range (g), it is output to the delay circuit 14 and the AND circuit 15.

The delay circuit 14 delays the out-of-tolerance signal manually inputted from the comparison circuit 13 by a predetermined period of time and outputs the out-of-tolerance signal. It will be done. Here, the AND circuit 5 outputs a motor lock detection signal when the out-of-tolerance signal from the comparator circuit 13 and the out-of-measurement-range delay signal from the delay circuit 14 are simultaneously input. In other words, when the comparator circuit 13 obtains a signal outside the allowable range,
If this state continues for a predetermined time or more in the delay circuit 14, a motor lock detection signal will be obtained from the AND circuit 15.

FIG. 2 shows another embodiment of the motor lock detection device, and the same components as those in FIG.

First, the out-of-tolerance signal output from the comparator circuit 13 is
One side is inputted directly to the integrating circuit 16, and the other side is inputted via an inverter.

That is, the integrating circuit 16 integrates the time during which the out-of-tolerance signal is input from the comparator circuit 13 and outputs a time signal corresponding to the human power time. is output to. In this case, the integration circuit 16 is reset at the same time as the out-of-tolerance signal disappears.

The comparator]8 inputs a predetermined time reference value from the time reference generation circuit 17, and the time signal value from the integration circuit]6 corresponding to the output time of the out-of-tolerance signal exceeds the time reference value. In other words, if a motor current value out-of-tolerance signal is continuously output for a predetermined period of time or more, a motor lock detection signal is obtained.

FIG. 3 shows the internal configuration of the comparison circuit 13 in FIGS. ．． 32 and an OR circuit 33, the comparator 31 compares the current command value or current detection value of the motor with the positive reference value from the positive reference generation circuit 11, and determines whether the current command value or current detection value is the positive reference value. If the value is higher than that, the output becomes high level. Further, the comparator 32 compares the current command value or current detection value of the motor with the negative reference value from the negative reference generation circuit 12, and outputs high when the current command value or current detection value is less than or equal to the negative reference value. become the level. Then, when the output of either the comparator 31 or 32 becomes a high level, the OR circuit 33 outputs a high level and outside the allowable range (No. 5 is output).

Therefore, according to the motor lock detection device having the above configuration, if the current command value or current detection value of the motor continues to deviate from the predetermined reference value for a predetermined period of time or more, an out-of-tolerance signal is output and the motor is activated. Since the locked state is detected, for example, even if a large current flows temporarily during starting, stopping, and reversal of the electric motor, it is possible to prevent this from being erroneously determined as being in the locked state.

Further, since the locked state is not determined by speed detection, continuous operation can be performed at any low speed without worrying about the determined state of the motor lock.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As described above, according to the present invention, there is provided a reference value deviation detection means for detecting that a current command value or a detected current value of a motor deviates from a predetermined reference value, and a Since the device is equipped with a lock determination device that determines that the motor is locked if the reference value deviation detection device continues for a predetermined period of time or more, there is no misjudgment when starting, stopping, or reversing the motor, and the set value for low speed detection can be adjusted. It is possible to provide a motor lock detection device that can accurately detect the locked state of a motor without the need for modification.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a motor lock detection device according to an embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the invention, and FIG. 3 is a comparison of the above motor lock detection devices. FIG. 2 is a block configuration diagram showing a circuit. 11... Positive reference generation circuit, 12... Negative reference generation circuit, 13... Comparison circuit, 14... Delay circuit, 15...
- AND circuit, 16... Integrating circuit, 17... Time reference generation circuit, 18... Comparator.

Claims (1)

[Claims] Reference value deviation detection means detects that the current command value or current detection value of the motor deviates from a predetermined reference value, and if the reference value deviation detection state by the reference value deviation detection means continues for a predetermined time or more, the electric motor An electric motor lock detection device comprising lock determination means for determining that the motor is locked.