JP2561845B2 - Inverter device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an inverter device for controlling the speed of an induction motor by frequency control, and particularly to a start-up.
The present invention relates to a stop command input device, for example, a connection circuit for a start-stop switch.

[Prior Art] FIG. 3 is a block diagram showing a conventional inverter device.
As a start command input device (hereinafter, referred to as a start switch) for starting operation of an inverter device (hereinafter, referred to as an inverter) or as a stop command input device (hereinafter, referred to as a stop switch) for stopping It is a figure using a return type (which has a mechanism that returns to the original position when the operating force is removed and is usually called a push button switch).

In the figure, (1) indicates an inverter. (2) is a start input terminal (hereinafter referred to as ST terminal), and (3) is a stop input terminal (hereinafter referred to as STP terminal). (4) is a common terminal (hereinafter referred to as COM terminal) of the ST terminal (2) and the STP terminal (3), which is connected to the common circuit inside the inverter (1). Also, ST terminal (2), STP terminal (3), C
The OM terminal (4) is equipped on the inverter (1).
(5) is a push button switch for starting the inverter (1), a contact type, and (6) is a push button switch for stopping, which is a b contact type. (41) is a power supply for a start and stop signal circuit described later, and the opposite pole corresponding to this power supply (41) has a common circuit (4) to which the COM terminal (4) is connected.
4).

Reference numerals (42) and (43) are a start signal circuit and a stop signal circuit, respectively, which are operated by operating the start push button switch (5) or the stop push button switch (6) to start the inverter (1). Alternatively, it is a circuit that outputs a stop signal.

(45) is a control circuit of the inverter (1), receives the output signals of the start signal circuit (42) and the stop signal circuit (43) to control the start or stop of the operation of the inverter (1), and This circuit controls the operation of the main circuit (46). (46) shows the main circuit of the inverter (1), which converts the main circuit input (47) AC power into DC, converts the converted DC into AC power of an arbitrary frequency and voltage, and outputs the main circuit output. The rotation speed of the AC electric motor (49) connected to (48) is controlled.

FIG. 4 is a time chart when the push button switches (5) and (6) are operated in the configuration of FIG. (11) indicates that the push button switch (5) and (12) indicates that the push button switch (6) has been operated for a short time (pulse-shaped for about 1 second), respectively, and as a result, the ST terminal (2) And start signal circuit (42) via STP terminal (3)
And that the signal was correctly transmitted to the stop signal circuit (43). (13) indicates that the inverter (1) has been started by the signal (11) and has entered the operating state, and then the inverter (1) has entered the stop operation by the signal (12) and then entered the stopped state. Indicates.

Next, (14) pushes the pushbutton switch (5) again (1
Similarly, 5) shows a signal when the push button switch (6) is simultaneously operated. (16) is the input signal (14) of the start signal circuit (42) as a result of simultaneous output of the signal (14) and the signal (15).
Priority is given to the fact that the inverter (1) has started to start and is in the operating state, and at the same time, the operation of the push button switches (5) and (6) has been stopped to enter the stop operation and then stop. Shows.

Fig. 5 shows the same inverter (1) as in Fig. 3, and a snap switch as a start-stop switch (off "OFF"->"ON" direction, even after removing the operating force, This is a switch that has a mechanism that allows the switch itself to hold the ON state. The same holds when operated in the ON → OFF direction. It is a connection circuit that uses the inverter (1).
(41) to (48) and (49) are omitted from the figure.

In the figure, (1) to (4) are the same as the parts denoted by the same reference numerals in FIG. (7) is a snap switch.

Further, FIG. 6 is a time chart when the snap switch (7) is operated in the configuration of FIG.
Reference numeral (21) shows a signal input to the start signal circuit (42) according to the ON operation of the snap switch (7). (22) indicates that when the snap switch (7) is turned on, the inverter (1) starts to start, and when it is turned off, the inverter (1) enters a stop operation and then enters a stop state.

Next, FIG. 7 shows a case where a push button switch type such as (5) and (6) in FIG. 3 is used as a start-stop switch, and a snap switch as shown in FIG. 5 (7). One of the methods of using the shape is connected to the same terminal of the inverter (1), and the inverter (1) does not require any selection operation, regardless of the input form of the start signal or the stop signal. 7 is a flowchart showing the operation of the circuit configured to perform the starting or stopping operation as it is.

The above circuit is included in the control circuit (45) and will be referred to as a start / stop circuit.

The start / stop circuit is based on a program stored in advance in a memory (not shown) in the control circuit (45).
It operates under the control of a CPU (central processing unit, not shown) in the control circuit (45).

That is, in step (31), the inverter (1) is stopped. Starting signal circuit (42) in step (32)
If it is OFF, the process returns to step (31). If it is ON, the inverter (1) is put into operation. In step (34), the input of the stop signal circuit (43) is discriminated, and if ON, the process returns to step (33), and if OFF, the process returns to step (32).

 Next, the operation will be described.

The control circuit (45) of the inverter (1) has a built-in start / stop circuit that operates according to the flowchart shown in FIG. For this reason, when the push button switch (5) in FIG. 3 is operated in a pulsed manner, the inverter (1) is started, and when the stop push button switch (6) is input in a pulsed manner, the inverter (1) is turned on. Stop.

Also, with the configuration shown in FIG. 5, when the snap switch (7) is turned on, the inverter (1) starts starting,
The operation is continued while the snap switch (7) is ON.
Then, when the snap switch (7) is turned off, the inverter (1) starts decelerating and stops. The reason why the stop operation starts immediately when the snap switch (7) is turned off is that the STP terminal (3) in the configuration of FIG.
Since the stop push button switch (6) in FIG. 3 is not connected, the circuit in the inverter (1) is regarded as operating the switch (6) in the OFF state.

As described above, even if the inverter (1) has the configuration shown in FIG. 3 or the configuration shown in FIG. 5, the circuit of the flowchart shown in FIG. 7 does not need to switch the internal circuit. Are equipped with.

Therefore, when the pushbutton switches (5) and (6) are connected in parallel as shown in the configuration of FIG. 3, the pushbutton switches (5) and (6) are simultaneously connected as shown in signals (14) and (15) of FIG. ) And (6) are operated, the inverter (1) is started. This will be described with reference to FIG.

By the simultaneous operation, the input determination of the start signal circuit in step (32) is turned on, and the inverter is in the operating state after starting in step (33). Although the determination of the stop signal circuit input in step (34) is OFF, the process returns to the determination of the start signal circuit input in step (32).

In this way, step (32) → ON → step (33) → step (34) → OFF → step (32), so that the inverter (1) continues to operate during the simultaneous operation.

[Problems to be Solved by the Invention] Since the conventional inverter is configured as described above, the operation-stop switch is configured by a push button switch, and the switches are connected in parallel as shown in FIG. When connected, the start / stop circuit of the inverter (1) is configured to operate normally even with the snap switch type. Therefore, when the pushbutton switches are simultaneously operated, the inverter (1) will start. Becomes a circuit,
It was a particular safety issue that the willingness to stop was ignored.

The present invention has been made to solve the above problems, and while maintaining the feature that the push button switch system and the snap switch system can be connected without a switching operation, the operation is stopped when they are operated simultaneously. The purpose is to obtain an inverter that does.

[Means for Solving Problems] An inverter device according to the present invention controls a main circuit unit that converts alternating current into direct current and converts the converted direct current into alternating current of an arbitrary frequency, and the main circuit unit. An inverter device including a control unit, wherein a start signal unit that controls a start operation of the inverter device, a stop signal unit that controls a stop operation of the inverter device, and a common start signal unit and a stop signal unit A power supply unit having one of a positive potential and a negative potential connected to each other,
A start input terminal connected to the start signal section, a stop input terminal connected to the stop signal section, and a potential different from the potential of the power supply section and connected to each of the start signal section and the stop signal section In the inverter device, which includes a common terminal that operates, the operation of the start signal unit is prioritized when signals are simultaneously input to the respective signal units between the start signal unit and the stop signal unit, 1) As a start command input means of the in butter device,
When one of the command input means that opens after a predetermined time after closing and the command input means that opens after a predetermined time after opening is used and the other is used as the stop command input means, the above command input One of the closed contact and the open contact of the means is connected between the start input terminal and the stop input terminal, and the other is connected between the stop input terminal and the common terminal.

(2) When the command input means of the inverter device, which is closed and then opened by giving a predetermined operation, is used, the command input means is connected between the start input terminal and the common terminal. .

It is configured as follows.

[Operation] In the present invention, when the start command input device is connected between the start input terminal and the stop input terminal and the stop command input device is connected between the stop input terminal and the common terminal, the start command input device is started when the two are operated simultaneously. The inverter does not start starting because no signal is formed.

[Embodiment of the Invention] An embodiment of the present invention will be described below.

In FIG. 1, (1) to (6) and (41) to (4
9) is the same as the part with the same reference numeral in FIG. However,
The push button switches (5) and (6) are connected in series.

In FIG. 2, (11) to (15) are the same as the parts denoted by the same reference numerals in FIG. In addition, in FIG. 2, (1 in FIG.
There is no one corresponding to 6). This indicates that the inverter (1) does not start when the push button switches (5) and (6) shown in FIG. 1 are simultaneously operated.

 Next, the operation will be described with reference to FIGS. 1 and 2.

When the start push button switch (5) is turned on to start the inverter (1), the signal is the power supply (41) -start signal circuit (42) -ST terminal (2) -start push button switch (5). ) -Stop push button switch (6) -COM terminal (4) -Common circuit (44) circuit, the start signal circuit (42) detects the ON operation of the switch (5), and the start signal circuit (42) ) Output is transmitted to the start / stop circuit of the control circuit (45), and the inverter (1) operates. In addition, the stop signal continues to flow through the circuit of power supply (41) -stop signal circuit (43) -STP terminal (3) -stop push button switch (6) -COM terminal (4) -common circuit (44). Continue driving.

Next, when the stop push button switch (6) is turned off, the STP terminal (3) -stop push button switch (6)
The route of the -COM terminal (4) is turned OFF, the stop signal circuit (43) detects the OFF operation of the switch (6), and the output of the stop signal circuit (43) is transmitted to the start / stop circuit. At this time, the start push button switch (5) is already OF
Since it is F, the inverter (1) starts the stop operation.

The above is the operation when the normal operation is performed, and since this operation is the same operation as the conventional inverter shown in FIG. 3, it is not affected by the change in the operation result due to the connection change.

Further, when the pushbutton switches (5) and (6) are simultaneously operated as an abnormal operation, even if the switch (5) is turned on, the stop pushbutton switch (which is connected in series with the switch (5) ( Since 6) is turned off, the stop signal circuit (43) detects the operation of the stop push button switch (6) and the inverter (1) does not start. When operated simultaneously, the route of ST terminal (2) -switch (5) -STP terminal (3) is formed, but the same potential is applied between ST terminal (2) and STP terminal (3), It cannot be the start signal of (1) and does not malfunction. Because the current flows from the positive pole to the negative pole, in this simultaneous operation, the start signal circuit (42) and the stop signal circuit (4
Since the power supply (41) for the circuit of 3) is the same, that is, the current is the same polarity, the current is the power supply (41) -start signal circuit (42) -ST terminal (2) -switch (5) -STP terminal (3) -stop. This is because it cannot flow in the route of the power supply (41) for the signal circuit (43) -stop signal circuit (43), and the start signal circuit (42) does not operate.

 Next, another embodiment will be described.

(A) In the above-described embodiment, the push button switches (5) and (6) are used as the start and stop command input devices, but they may be configured with contacts such as contacts of an electromagnetic relay,
A contactless switch such as a transistor may be used.

(B) The switches (5) and (6) may be installed outside the inverter (1) or may be attached to the inverter (1).

(C) The signal of each terminal (2), (3), (4) is "ST",
Although shown as “STP” and “COM”, any symbols may be used.

(D) Switches (5) and (6) are shown as a-contact and b-contact, respectively, but when they are operated at the same time, one of them is turned off.
Any combination of

(E) The switches (5) and (6) have been described as being operated artificially, but even if they are in the same state as simultaneous operation due to a failure such as insulation failure or wire breakage, the start signal of the inverter (1) Therefore, accidents due to malfunctions can be prevented.

(F) Although the starting circuit is shown as only one circuit (only in the forward rotation direction), two circuits (forward rotation and reverse rotation circuits) may be provided and a stop circuit may be connected in series to these two circuits.

EFFECT OF THE INVENTION As described above, according to the present invention, the start command input device is connected between the start input terminal and the stop input terminal, and the stop command input device is connected between the stop input terminal and the common terminal. If operated, the start signal will not be generated and the inverter will not start. Therefore, there is an effect that the safety is improved.

Further, since it is only necessary to change the connection, it is not necessary to change the cost of additional parts or the internal circuit, and the cost does not increase.

Further, it is possible to prevent the automatic start of the inverter due to a failure such as insulation failure or disconnection, so that the device becomes safer.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the embodiment shown in FIG. 1, and FIG. 3 is a block diagram showing a conventional inverter. 4 is a flow chart for explaining the operation of the inverter shown in FIG. 3, FIG. 5 is an explanatory view for explaining another example of the conventional inverter, and FIG. 6 shows the operation of the inverter shown in FIG. Time chart for explanation, Fig. 7 shows start /
It is a flow chart which shows operation of a stop circuit. In the figure, (1) is an inverter, (2) is a start input (ST) terminal, (3) is a stop input (STP) terminal, (4) is a common (COM) terminal, and (5) is a pushbutton switch for starting. , (6) is a stop push button switch, (42) is a start signal circuit, (43) is a stop signal circuit, (45) is a control circuit,
(46) is a main circuit, and (49) is an AC motor. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. An inverter device comprising a main circuit section for converting an alternating current into a direct current and converting the converted direct current into an alternating current having an arbitrary frequency, and a control section for controlling the main circuit section, wherein: A start signal section that controls the start operation of the inverter device,
A stop signal section that controls the stop operation of the inverter device,
A power supply unit having one of a positive potential and a negative potential commonly connected to the start signal unit and the stop signal unit, a start input terminal connected to the start signal unit, and connected to the stop signal unit. And a common terminal connected to each of the start signal section and the stop signal section, having a potential different from that of the power supply section, and between the start signal section and the stop signal section. In an inverter device in which the operation of the start signal part takes precedence when signals are simultaneously input to the respective signal parts, an inverter characterized by connecting command input means to the inverter device according to the following configuration apparatus. (1) As a start command input means of the inverter device,
When one of the command input means that opens after a predetermined time after closing and the command input means that opens after a predetermined time after opening is used and the other is used as the stop command input means, the above command input means Connect either one of the closed contact or open contact between the start input terminal and the stop input terminal,
The other is connected between the stop input terminal and the common terminal. (2) When the command input means of the inverter device, which is closed and then opened by giving a predetermined operation, is used, the command input means is connected between the start input terminal and the common terminal. .