JPH0767384A - Motor driving device - Google Patents

Abstract

PURPOSE:To operate a motor continuously even if one switch fails by determining the order of operation of a double switch in advance. CONSTITUTION:Double parallel non-contact switches 6A and 6B which are switched based on operation commands 5A and 5B of a motor, a voltage monitoring part 7 which is connected between terminals X and Y of the switches 6A and 6B and outputs a voltage signal 7S by detecting the presence or absence of a voltage applied between the terminals X and Y, and a failure detection part for displaying the failure by detecting the operation failure of the switches 6A and 6B are provided, thus operating the switches 6A and 6B provided in a double alternately for each operation.

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 having a double non-contact switch with a failure detection section.

[0002]

2. Description of the Related Art In a switch used for driving a motor, each switch may be doubly connected in parallel in order to ensure its reliability. The switches are duplicated, and each switch is provided with a failure detection unit.
Even if one switch fails, the failed switch is immediately detected, so that the motor can be operated by the other switch. Therefore, the operation of the motor is not stopped for a long time, and the broken switch can be repaired during the operation.

FIG. 1 is a circuit diagram showing the structure of a motor drive device. Output side R-phase, S-phase, and T-phase connection lines R, S, and T of the three-phase power source 1 are connected to a three-phase circuit breaker 13.
On the output side of the circuit breaker 13, the S-phase connection line S is directly connected to the 3-phase motor 2, but the R-phase and T-phase connection lines R and T are respectively connected via the forward rotation switches 3R and 3T. Connected to the motor 2. Further, in FIG. 1, reverse rotation switches 4R and 4T are provided between the connecting lines R and T and between the connecting lines T and R, respectively.

In FIG. 1, forward rotation switches 3R and 3T are provided.
The internal configurations of the reverse rotation switches 4R and 4T will be described in detail later, but the forward rotation switches 3R and 3T and the reverse rotation switches 4R and 4T are closed based on the operation command 5A or 5B. When the forward rotation switches 3R and 3T are closed and the reverse rotation switches 4R and 4T are opened, the motor 2 rotates in the forward direction. On the other hand, when the normal rotation switches 3R and 3T are opened and the reverse rotation switches 4R and 4T are closed, the R phase and the T phase are exchanged, so that the motor 2 rotates in the reverse direction.

FIG. 2 is a circuit diagram showing the internal structure of the forward or reverse switch of FIG. Forward rotation switches 3R, 3
In both cases of the T and the reverse rotation switches 4R and 4T shown in FIG. 1, two contactless switches 6A and 6B (in the dotted frame) are connected in parallel between the terminals X and Y in a double line. Also, terminals X and Y
Further, a voltage monitoring unit 7 (inside a dotted line frame) is connected in parallel between them. The operation signal 5 is applied to the non-contact switches 6A and 6B.
A and 5B are input, and the operation signals 5A and 5B are input to the failure detection units 8A and 8B together with the voltage signal 7S output from the voltage monitoring unit 7, respectively.

In FIG. 2, contactless switches 6A and 6B are provided.
Is composed of an optical thyristor 9 as an optical semiconductor switching element which is connected in antiparallel with each other, and a light emitting diode 10 which emits light 10A as a gate signal to the optical thyristor 9. The light emitting diode 10 has an operation signal 5A,
When it receives 5B, it emits light to turn off the optical thyristor 9 to close the terminals X and Y. In FIG. 2, N on the cathode side of the light emitting diode 10 indicates that it is connected to a negative electrode of a DC power source (not shown).

Further, in FIG. 2, the voltage monitoring section 7 is composed of a light emitting diode 12 which is anti-parallel to each other via a resistor 14 and a phototransistor 11 which receives a light 12A emitted from the light emitting diode 12, and the phototransistor 11 is provided. The collector side is connected to the anode of a DC power supply (not shown), and the voltage signal 7S is output from the emitter side. When an AC voltage is generated between the terminals X and Y, the light emitting diode 12
Either of the two becomes conductive and emits light, and this light 12A is converted into an electric signal by the photodiode 11 and becomes a voltage signal 7S. That is, when a voltage is applied between the terminals X and Y of the contactless switches 6A and 6B, the voltage monitoring unit 7 outputs the voltage signal 7S.

FIG. 3 is a logic circuit diagram showing the internal structure of the failure detection unit of FIG. The operation signal 5A or 5B and the voltage signal 7S are input to the NOR circuit 17 and the AND circuit 18, and the output signals of the NOR circuit 17 and the AND circuit 18 are input to the OR circuit 21 via the timers 19 and 20, respectively. The output signal of the OR circuit 21 is input to the display unit 22. In FIG. 3, the NOR circuit 17 outputs a signal only when there are no two input signals, and the AND circuit 18 outputs 2 signals.
It outputs a signal only when there are two input signals. The timers 19 and 20 output a signal only when the input signal continues for a predetermined time, and the OR circuit 21 outputs a signal when the input signal exists in at least one of the two input signals. When the display unit 22 receives an output signal from the OR circuit 21, the display unit 22 gives an alarm and turns on a lamp for determining a malfunctioning contactless switch.

Therefore, the switch failure is detected in FIG. 3 in the following two modes. Failure mode (1): The voltage signal 7S is output when the operation command 5A or 5B is issued. Failure mode (2): The voltage signal 7S is output when the operation command 5A or 5B is issued.

That is, the failure mode (1) is the NOR circuit 1
When 7 outputs a signal, the failure mode (2) corresponds to the case where the AND circuit 18 outputs a signal. Returning to FIG. 1, for example, when the normal rotation switch 3R is normal, when the operation command 5A is given, the normal rotation switch 3R is closed, and no voltage is generated between its terminals X and Y. Therefore, FIG.
No voltage signal 7S is output from the voltage monitoring unit 7 of FIG. Here, even though the forward rotation switch 3R is out of order and the operation command 5A is given, the forward rotation switch 3R
When R remains open, a voltage is generated between the terminals X and Y and the voltage monitoring unit 7 outputs the voltage signal 7S. This corresponds to the failure mode (2) described above, and the failure detection unit 8
A displays a fault.

If the forward rotation switch 3R is out of order and the operation command 5A is not given, but the forward rotation switch 3R remains closed, a voltage is generated between its terminals X and Y. Therefore, the voltage signal 7S is not output from the voltage monitoring unit 7. This corresponds to the failure mode (1), and the failure detection unit 8A displays the failure. The same applies to the other forward rotation switches 3T and reverse rotation switches 4R and 4T.

As mentioned above, a switch failure can be detected by the device of FIG. In FIG. 2, the two contactless switches 6A and 6B are arranged in order to enhance the reliability of the motor drive device, as described above.
This is because the switch is duplicated. Solid state switch 6
Even if one of A and 6B fails, the other can be used to continue the operation of the motor, and the one that failed during the operation can be repaired. In FIG. 2, the failure detection units 8A and 8B are the contactless switches 6A and 6B.
It is provided corresponding to B. This is for promptly displaying which contactless switch (there are eight in total in FIG. 1) when a failure occurs.

Although FIG. 2 shows an example of a contactless switch, a contact type switch can be used as the forward rotation and reverse rotation switches of FIG. 1, and the failure can be detected by the same method. .

[0014]

However, in the conventional device as described above, since the operation order of the switches provided in duplicate is determined, there is a case where one switch failure cannot be detected early. There was a problem. In other words, with regard to the double switch, if the switch opening / closing operation is always performed by the operation signal of one switch,
It will be impossible to detect the presence or absence of a failure of the other switch at all. In this state, if one switch fails and you switch to the other switch, it should work normally, but if you find that the switch you switched to is also defective, repair the switch. The motor must be stopped until the end. With this, there is no meaning to duplicate the switch. It is an object of the present invention to predetermine the operation order of the double switches so that the motor can be continuously operated even if one switch fails.

[0015]

In order to achieve the above object, according to the present invention, a power source for supplying power to a motor and a power source interposed between the power source and the motor are opened and closed based on an operation command. A switch malfunction is detected based on the switch, the voltage monitoring unit that is connected between the terminals of the switch and detects the presence or absence of a voltage applied between the terminals, and outputs a voltage signal, and the switch operation command and the voltage signal of the voltage monitoring unit. A switch provided with a failure detection section that detects and displays a failure, and in which two switches are connected in parallel and the failure detection section is provided in each switch Are alternately operated for each operation.

Further, in such a structure, the switch is a non-contact switch composed of a semiconductor switching element.

[0017]

According to the structure of the present invention, the switches provided in double are alternately operated for each operation, so that the use of the switches is not biased to one side. Therefore, it is possible to confirm the presence / absence of a failure of both switches at the same frequency each time the motor is driven or reversed. Therefore, the failure of the switch can be detected at an early stage, and even if one switch fails, the other switch can be used to continuously operate the motor. Moreover, it is possible to repair one switch while the motor is operating.

[0018]

Embodiments of the present invention will be described below with reference to FIGS. In FIG. 1, operation commands 5A and 5B of the forward rotation switches 3R and 3T and the reverse rotation switches 4R and 4T are alternately sent for each operation, and the contactless switches 6A and 6B connected in parallel in FIG. Operate alternately.
By determining the operation order of the contactless switches 6A and 6B in advance, it is possible to confirm whether or not there is a failure in the switches 6A and 6B at the same frequency as each other, and as a result, the failure in the switches 6A and 6B is found early. can do.

Although FIG. 2 shows the case of the contactless switch, the same applies to the case of the contact method, and the failure of the switch can be prevented by alternately operating the switches connected in parallel in double. It can be discovered early.

[0020]

As described above, according to the present invention, the switches provided in double are alternately operated for each operation.
It became possible to detect switch failures early. Therefore, it is not necessary to stop the operation of the motor due to the failure of the switch, and the reliability of the device is significantly improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a motor drive device.

FIG. 2 is a circuit diagram showing an internal configuration of a forward rotation switch or a reverse rotation switch shown in FIG.

FIG. 3 is a logic circuit diagram showing an internal configuration of the failure detection unit of FIG.

[Explanation of symbols]

1: power supply, 2: motor, 3R, 3T: forward rotation switch,
4R, 4T: reverse rotation switch, 5A, 5B: operation command,
6A, 6B: non-contact switch, 7: voltage monitoring unit, 7A:
Voltage signal, 8A, 8B: Failure detection unit, 9: Optical thyristor, 10, 12: Light emitting diode, 11: Phototransistor, 13: Circuit breaker, 14: Resistor, 12A, 10A:
Light, 17: NOR circuit, 18: AND circuit, 19, 20:
Timer, 21: OR circuit, 22: display, X, Y: terminals

Claims (2)

[Claims] 1. A power supply for supplying power to a motor, a switch interposed between the power supply and the motor and opening / closing based on an operation command, and a switch connected between terminals of the switch to determine whether a voltage is applied between the terminals. It is composed of a voltage monitoring unit that detects and outputs a voltage signal, and a failure detection unit that detects a malfunction of the switch based on the operation command of the switch and the voltage signal of the voltage monitoring unit and displays a failure. A motor drive device in which one switch is provided in parallel and another switch is provided with a failure detection unit, and switches provided in double are alternately operated for each operation. . 2. The motor drive device according to claim 1, wherein the switch is a contactless switch including a semiconductor switching element.