JPH0767258A - Parallel operation connection unit for ac power suppely unit - Google Patents

Abstract

PURPOSE:To prevent the output voltage of another operating generator from appearing at the power supply terminal of a plug removed from a generator during parallel operation thereof even if the earth terminal of the plug is conducted (short-circuited) with a terminal dedicated for earth. CONSTITUTION:The parallel operation connection unit 30 is provided with a push button switch for connecting the output line from a unit 30a with that from another unit 30b. Even if a plug 6 is removed from a generator 2 during parallel operation and the earth terminal 6c thereof is conducted with a terminal 5 dedicated for earth, the output lines are not conducted each other so long as the push button is not depressed. Consequently, output voltage from another operating generator 2 does not appear at the power supply terminals 6a, 6b of the removed plug 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel operation connection unit for superimposing outputs of respective AC power supply units when a plurality of AC power supply units are operated in parallel.

[0002]

2. Description of the Related Art When a plurality of AC power supply units are operated in parallel, a parallel operation connection unit for superimposing and outputting the outputs of the AC power supply units is required.

Conventionally, when performing parallel operation using such a parallel operation connection unit, it is necessary to synchronize the phases of the AC outputs from the respective AC power supply units. In the case of the engine, the AC output voltage waveform of the engine generator that was started first is synchronized with the AC output voltage waveform of the engine generator that is started later. It is necessary to input the AC output voltage waveform of the started engine generator as a detection signal for aligning the phases. Therefore, the AC output voltage waveform of the engine generator that was previously started is output to the power supply terminal of the outlet plug of the AC power supply unit.

For this reason, the outlet plug may be removed from the outlet of the power supply unit by some external force during normal parallel operation, or the number of power supply units to be operated in parallel may be less than the number of outlet plugs of the connection unit, and the outlet plug may be left over. If this happens, the output voltage of the operating power supply unit to which the outlet plug is connected will appear as it is between the power terminals of the outlet plug that is exposed due to disconnection or excess, and care must be taken when handling it.

On the other hand, the applicant of the present application, as shown in FIG. 3, is exposed even if there is an outlet plug which is not connected to the outlet of the power supply unit among the outlet plugs. It proposes a connection unit for parallel operation in which an output voltage does not appear between the power supply terminals which are set to (Japanese Patent Application No. 3-283555).
That is, in the parallel operation connection unit, when the grounded outlet plugs 106 which are not connected to the generator 102 are present, these grounded outlet plugs 106 are provided.
Since the ground terminal 106c and the dedicated ground terminal 105 are open, the switch 11 of the relay 113
3a and 113b are turned off, and the power supply terminals 106a, 10a of the grounded outlet plug 106 to which the output voltage from the generator 101 input to the grounded outlet plug 103 connected to the generator 101 is not connected.
Does not appear on 6b.

[0006]

However, when the generator is in a special working environment, for example, when it is placed on a conductive table such as an iron plate, it is not possible to operate it in parallel as shown in the lower part of FIG. When the outlet plug 106 is pulled out and its ground terminal 106c comes into contact with a conductive plate such as the iron plate 150 on which the generator 102 is placed, a dedicated earth terminal that remains connected to the main body of the generator 102. 1
05 and the earth terminal 106c are the generator 102, the conductive plate 1
Since it becomes conductive (short-circuited) via 50, the switches 113a and 113b of the relay 113 described above are turned on, and the power supply terminals 106a and 10 of the outlet plug 106 are connected.
There was a case where the output voltage appeared on 6b.

Therefore, according to the present invention, even if the earth terminal of the outlet plug and the earth-dedicated terminal are conducted (short-circuited) while the outlet plug is detached from the generator during the parallel operation, another power source terminal of the detached outlet plug is provided. An object of the present invention is to provide a connection unit for parallel operation in which the output voltage of the generator during operation does not appear.

[0008]

In order to solve the above-mentioned problems, a connection unit for parallel operation of an AC power supply unit of the present invention has a pair of power supply terminals which can be inserted into an outlet provided at an output portion of the AC power supply unit. And a grounding terminal integrally provided with a grounding outlet plug, and a grounding dedicated terminal that is paired with the grounding outlet plug and is attachable to the AC power supply unit independently of the grounding outlet plug. A primary coil of a transformer connected between the pair of power supply terminals of the attached outlet plug and a secondary side of the transformer, and between the ground terminal of the outlet plug with earth and the dedicated earth terminal. A power supply circuit for generating a low-voltage current in the connected output line, and the low-voltage current generated by the power supply circuit for excitation Unit for parallel connection of AC power supply units, in which a plurality of unit units each having a first switch circuit for connecting the pair of power terminals of the outlet plug with a power supply to an output outlet are provided in common with the output outlet. And a second switch circuit for starting parallel operation, which connects the output line of at least one unit unit with the output line of another at least one unit unit, and the second switch circuit is turned on. And an operator for cutting.

[0009]

In the connection unit for parallel operation of the AC power supply unit of the present invention, a plurality of unit units having a common output outlet is provided, and at least one of the unit units is connected by the second switch circuit for starting parallel operation. The output line can be connected to the output line of at least one of the other unit units, and the second switch circuit connects and disconnects the output lines with each other by an operator operated by a worker at the start of parallel operation.

[0010]

EXAMPLE Next, an example of the connection unit for parallel operation of the AC power supply unit of the present invention will be described.

[First Embodiment] FIG. 1 is a circuit diagram showing an electrical configuration of a parallel operation connection unit 30 of the first embodiment. Each of the generators 1 and 2 is an independent power supply unit, and an outlet into which an outlet plug 3 or 6 with a ground can be inserted is provided at its output portion, and earth terminals for attaching the earth-dedicated terminals 4 and 5 are provided in one of the cases. I have it. (The illustration is omitted because it is a very general configuration, but the ground of the outlet and the ground terminal are electrically connected).

The parallel operation connection unit 30 of this embodiment is composed of two unit units 30a and 30b which share a push button switch 25 and an output outlet 17 which will be described later. The grounded outlet plugs 3, 6 have a pair of power supply terminals 3a, 3b and 6a, 6b, and ground terminals 3c, 6c, respectively. The power supply terminal 3a is a relay 8
Is connected to the power supply terminal 17a of the output outlet 17 for superimposing and outputting the output voltages of the generators 1 and 2 via the contact 8a of, and the power supply terminal 3b is connected via the contact 8b of the relay 8 to
It is connected to the power supply terminal 17b of the output outlet 17. The power supply terminal 6a is connected to the power supply terminal 17a of the output outlet 17 via the contact 13a of the relay 13,
The power supply terminal 6b is connected to the power supply terminal 17b of the output outlet 17 via the contact 13b of the relay 13.

The primary coil 10a of the transformer 10 is connected between the power supply terminals 3a and 3b in parallel with the contacts 8a and 8b of the relay 8, and the contact 13a of the relay 13 is provided between the power supply terminals 6a and 6b. , 13b are connected in parallel with the primary coil 15a of the transformer 15. A full-wave rectifier circuit 11 is connected to the secondary coil 10b of the transformer 10, and a full-wave rectifier circuit 16 is connected to the secondary coil 15b of the transformer 15.

The earth side of the full-wave rectifier circuits 11 and 16 is connected to the earth-dedicated terminals 4 and 5 and the earth terminal 17c of the output outlet 17. In addition, the full-wave rectifier circuit 1
The high potential side of 1 and 16 are smoothing capacitors 12 respectively.
a, 12b and the discharging resistors 22a, 22b are connected to the ground, and the exciting coils 8 of the relays 8, 13 are connected.
It is also connected to c and 13c. Also, the exciting coil 8
The other ends of c and 13c are connected to grounded outlet plugs 3 and 6
Of the earth terminals 3c and 6c. Further, surge current absorbing diodes 9 and 14 are connected in parallel with the exciting coils 8c and 13c. A self-recovery type push button switch 25 is connected between the high potential side output lines 11a and 16a of the full wave rectification circuits 11 and 16, and the push button switch 2 is held only while the push button switch 25 is being pushed.
The output lines 11a and 16a are electrically connected to each other through the line 5.

Next, the operation of the parallel operation connection unit 30 will be described. First, in order to perform parallel operation, the outlet plugs 3 and 6 with ground are inserted into the outlets of the generators 1 and 2. Next, when the generator 1 is started, the electric power of the generator 1 is supplied to the primary coil 10a of the transformer 10 via the grounded outlet plug 3 to excite the transformer 10, and the secondary coil 10b of the transformer 10 A voltage is generated between both ends. This secondary voltage is rectified by the full-wave rectifier circuit 11, and this rectified output is output to the capacitor 12
And is applied to the exciting coil 8c of the relay 8.

Already, the grounded outlet plug 3 is inserted into the generator 1, and at the same time, the earth-dedicated terminal 4 is also included in the generator 1.
Since it is attached to the full-wave rectifier circuit 11, the exciting coil 8c, the ground terminal 3 of the grounded outlet plug 3
c, a closed circuit is formed between the dedicated terminal 4 for earth and the earth-dedicated terminal 4, and the low-voltage current generated in the full-wave rectifier circuit 11 flows through this closed circuit. As a result, the contact 8a of the relay 8
8b is turned on, and the electric power of the generator 1 is output from the outlet 1
7 is supplied.

On the other hand, the grounded outlet plug 6 and the ground-only terminal 5 do not form a closed circuit including the exciting coil 13c of the relay 13 because the generator 2 is not activated, and the contacts 13a and 13b of the relay 13 are not formed. Remains off. Therefore, the output voltage from the generator 1 is the relay 13
Since the contacts 13a and 13b are disconnected, the output voltage does not appear in the grounded outlet plug 6.

Next, when the operator presses the push button switch 25 after confirming that the outlet plugs 3 and 6 are inserted in both the generators 1 and 2, while the push button switch 25 is being pressed, The rectified output of the full-wave rectifier circuit 11 flows to a closed circuit formed between the exciting coil 13c, the earth terminal 6c of the earthed outlet plug 6 and the earth-dedicated terminal 5 via the generator 2, so that the contact 13a of the relay 13 is formed. , The contact 13b is turned on, the AC output voltage of the generator 1 is the contacts 8a, 8b of the relay 8 and the contact 13a of the relay 13,
Power supply terminal 6 of the outlet plug 6 via the contact 13b
It will appear in a and 6b. The AC output voltage for synchronizing the generator 2 with the generator 1 is an outlet plug 6a,
When the generator 2 is started in the state of appearing in 6b, the generator 2 outputs an AC output voltage synchronized with the generator 1 and the parallel operation is started.

After the parallel operation is started, the relays 8 and 13 can be individually turned on by the outputs of the generators 1 and 2, respectively.

Next, during this parallel operation, the outlet plug 6 is disengaged from the generator 2 by some external force and the power supply terminals 6a, 6b and the ground terminal 6c are exposed, as shown in FIG. Even if the earth terminal and the earth-dedicated terminal are conducted through the placed iron plate, since the push button switch 25 is turned off in this embodiment, the relay 13 is released when the outlet plug 6 is detached from the generator 2. Is turned off and the contacts 13a, 13b are turned off, so that the AC output voltage of the generator 1 does not appear at the power supply terminals 6a, 6b. As described above, the unit units 30a and 30b
Have the same configuration, the above description is also applicable to the generator 1 side.

For the sake of clarity, the operation when the outlet plug is removed during parallel operation is shown, but it can be read that the relay 13 cannot be turned on from the beginning even at the start. The operation is exactly the same.

[Second Embodiment] Next, a parallel operation connection unit 50 of a second embodiment will be described. Figure 2 is the second
It is a circuit diagram which shows the electric constitution of the connection unit 50 for parallel operations of an Example. This parallel operation connection unit 50 is configured by adding a push button switch 250 and a switch circuit 55 in place of the push button switch 25 of the parallel operation connection unit 30 of the first embodiment. The same components as those in the first embodiment are designated by the same reference numerals. The switch circuit 55 includes a detection circuit 65, a delay circuit 71, a self-holding circuit 7
5 and relay circuit 82.

One contact 250a of the push button switch 250
Is a full-wave rectifier circuit 1 of each unit 30a, 30b.
The output lines 11a and 16a on the high voltage side of Nos. 1 and 16 are commonly connected via the diodes 51a and 56a, and the other contact 250b is connected to the exciting coil 8 of the relay 84 described later.
4a. The detection circuit 65 is a full-wave rectification circuit 11,
Inverter 6 connected to 16 output lines 11a, 16a
6, 68, NOR gates 69 for inputting the outputs of the inverters 66, 68, and an inverter 70. When a low-voltage current is output to both output lines 11a and 16a by the rectifying action of the full-wave rectifier circuits 11 and 16 as in the first embodiment, the detection circuit 65 changes the output terminal of the inverter 70 from the H level to the L level. Output a changing signal. The delay circuit 71 forms a known time constant circuit from the resistor 72 and the capacitor 73, and delays the time when the output voltage of the detection circuit 65 changes from the H level to the L level. The self-holding circuit 75 is composed of inverters 77 and 78 connected in two stages, and a series circuit of a resistor 79 and a diode 80 connected in parallel to the inverters 77 and 78. At the preparatory stage for starting only the generator 1, the signal line 77a and the signal line 80 sandwiching the inverters 77, 78 are provided.
Both a are H level voltages. This signal line 7
When 7a becomes L level, the signal line 80a also becomes L level, but once it becomes L level, even if an attempt is made to input an H level voltage to the signal line 77a, the diode 8 connected in parallel is connected.
Since 0 becomes conductive and the forward drop voltage is limited, the signal lines 77a and 80a cannot be returned to the H level voltage. In this way, the L level voltage is held.

The relay circuit 82 includes a transistor 87 for driving the exciting coil 84a of the relay 84, a surge current absorbing diode 85 connected in parallel with the exciting coil 84a, and a voltage dividing resistor for adjusting the input voltage of the transistor 87. 88 and 89 are provided.

The operation of the switch circuit 55 shown above will be described. First, similarly to the first embodiment, the outlet plugs 3 and 6 are inserted into the outlets of the generators 1 and 2, and first, when the generator 1 is started, the earth terminal 3c of the outlet plug 3 and the dedicated earth Since the terminal 4 is conducted via the generator 1 and a closed circuit is formed via the full-wave rectifier circuit 11, a low-voltage current for exciting the exciting coil 8c of the relay 8 flows from the full-wave rectifier circuit 11. As a result, the contacts 8a and 8b of the relay 8 are turned on, and the outlet plug 3
The power supply terminals 3a and 3b are connected to the power supply terminals 17a and 17b of the output outlet 17 to output an AC voltage.

On the other hand, the generator 2 in which the outlet plug 6 is inserted is not activated, and the full-wave rectification circuit 11
Since the output line 11a of the above is cut off by the output line 16a of the full-wave rectification circuit 16 and the relay 84, even if the earth terminal 6c of the outlet plug 6 and the dedicated earth terminal 5 are conducted through the generator 2, the relay 13 does not Not excited. In this state, the AC voltage output to the power supply terminals 8a and 8b of the outlet plug 8 is the power supply terminal 13a of the outlet plug 13,
It never appears on 13b.

At this time, the H-level voltage is input to the input of the inverter 66 by the full-wave rectifying circuit 11.
Since the other full-wave rectifier circuit circuit 13 does not perform the rectifying action, the L-level voltage signal is input to the input of the inverter 68. As a result, the output of the detection circuit 65 becomes H level via the NOR gate 69 and the inverter 70, and this H level output voltage is supplied to the base terminal 87a of the transistor 87 of the relay circuit 82 via the delay circuit 71 and the self-holding circuit 75. When it is input, the transistor 87 is turned on and the relay 84 is put in a standby state. Here, when the operator presses the push button switch 250, the terminals 250a and 250b are
Is turned on, and the collector side of the transistor 87 is connected to the output line 11a of the full-wave rectifier circuit 11. Therefore, when the transistor 87 is driven, a current flows through the exciting coil 84a and the contact of the relay 84 is turned on. When the contact of the relay 84 is turned on, the output line 1 of the full-wave rectifier circuit 11 is passed through this contact.
The contact of the relay 13 is also turned on by the output voltage of the output line 16a connected to 1a, and the power supply terminals 6a and 6b of the outlet plug 6 are connected to the power supply terminal 3a of the outlet plug 3.
The AC output voltage output from 3b comes to appear.

Power supply terminals 6a, 6b of the outlet plug 6
When the AC output voltage appears as described above, the input of the inverter 68 switches from the L level to the H level, and the input voltage of the inverter 66 is also the H level as described above. Therefore, the output voltage from the detection circuit 65 is delayed. The voltage gradually decreases according to the time constant CR of the circuit 71, and switches from the H level to the L level voltage after a lapse of a predetermined time. The delay circuit 71 is for ensuring the time until the relay 13 is turned on reliably. Once the signal line 77a
Is switched to the L level, the self-holding circuit 75 described above
Holds the voltage. Therefore, the transistor 87 is always in the OFF state, and even if the push button switch 250 is pressed in this state, the relay 84 is never excited again. At this stage, when the generator 2 is started, the parallel operation is started as in the first embodiment.

Next, when the outlet plug 6 is disengaged by some external force while the parallel operation is being performed, the contact of the relay 13 is turned off. Therefore, the power source terminals 6a and 6b of the outlet plug 6 are connected to the outlet plug 3. No AC output voltage appears. In addition, even when the earth-dedicated terminal 5 attached to the main body of the generator 2 and the earth terminal 6c of the outlet plug 6 are electrically connected by the conductive plate such as the iron plate on which the generator 2 is placed, the above-mentioned situation is caused. Since the relay 84 is not excited by the self-holding circuit 75 and its contact remains in the OFF state, the AC output voltage from the generator 1 in operation does not appear in the power supply terminals 6a and 6b of the outlet plug 6.

In this state, even if the push button switch 250 is pushed, the AC output voltage from the generator 1 in operation does not appear at the power supply terminals 6a and 6b of the outlet plug 6, which is different from the first embodiment. It is a feature.

In order to carry out the parallel operation again, both generators 1 and 2 must be temporarily stopped, the outlet 6 must be plugged in, and then restarted in accordance with the above procedure.

As described above, in the parallel operation connection unit 50 of the present embodiment, the ground terminal and the dedicated earth terminal of the outlet plug are electrically connected (short-circuited) with one outlet plug of the generator removed during parallel operation. Even if a case occurs, it is possible to prevent the AC output voltage of another running generator from appearing at the power supply terminal of the outlet plug in the disconnected state. Further, even if the push button switch 250 is pushed in this detached state, the AC output voltage of another generator in operation does not appear in the power terminal of the outlet plug in the detached state. Further, in order to restart the parallel operation, it is necessary to temporarily stop the output of both generators and then restart them, and the operation procedure is restricted, so that the operation is reliable.

The above embodiment can be variously modified without departing from the scope of the present invention. For example, since the push button switch is effective only once and is not effective even if pressed thereafter, it does not have to be a self-reset type. Further, in this embodiment, as the AC power supply unit, the voltage waveform of the AC output of the AC power supply unit that has been started first when the parallel operation is performed is detected, and the AC voltage is output by aligning the phase with the detected voltage waveform. However, the present invention is not limited to this (Japanese Patent Application No. 03-189142). Further, semiconductor switches such as triacs may be used instead of the relays 8 and 13.

[0034]

The parallel operation connection unit of the present invention turns on / off the second switch circuit for starting parallel output, which connects the output line of at least one unit unit to the output line of another at least one unit unit. Since the operator to do is provided,
Should the outlet plug come off the generator during parallel operation,
Moreover, even if there is a case where the ground terminal of the disconnected outlet plug and the dedicated ground terminal are conducted (short-circuited),
It is possible to prevent the output voltage of another running generator from appearing at the power terminal of the detached outlet plug.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an electrical configuration of a parallel operation connection unit 30 of a first embodiment.

FIG. 2 is a circuit diagram showing an electrical configuration of a parallel operation connection unit 50 of a second embodiment.

FIG. 3 is an explanatory diagram showing an electrical configuration of a conventional parallel operation connection unit.

[Explanation of symbols]

 1, 2 ... Generator 25 ... Pushbutton switch 55 ... Switch circuit 65 ... Detection circuit 71 ... Delay circuit 75 ... Self-holding circuit 82 ... Relay circuit

Claims (3)

[Claims] 1. A grounded outlet plug integrally provided with a pair of power supply terminals and a grounding terminal, which can be inserted into an outlet provided at an output portion of an AC power supply unit, and a pair with the grounded outlet plug, and A dedicated earth terminal that can be attached to the AC power supply unit independently of the grounded outlet plug; a primary coil of a transformer connected between the pair of power supply terminals of the grounded outlet plug; and a secondary coil of the transformer. A power supply circuit that is connected to the next side and that generates a low-voltage current in the output line that is connected between the ground terminal and the ground-only terminal of the grounded outlet plug, and is excited by the low-voltage current generated by the power circuit. A first switch for connecting the pair of power terminals of the grounded outlet plug to an output outlet, respectively. A unit for parallel operation connection of an AC power supply unit in which a plurality of unit units including a circuit are provided in common with the output outlet, wherein the output line of at least one unit unit is at least one other unit. A unit for parallel operation connection of an AC power supply unit, comprising a second switch circuit for starting parallel output, which is connected to the output line of the unit, and an operator for turning on / off the second switch circuit. 2. The unit for parallel operation connection of AC power supply units according to claim 1, wherein the operation element is a self-reset type push button switch. 3. The second switch circuit detects a switching circuit for turning on and off the contacts connected to the output line, and detecting that the contact of the switching circuit is turned on by the operation of the operator. And a detection circuit for outputting a detection signal, and a self-holding circuit for turning off the contact of the switching circuit by the detection signal and maintaining the contact of the switching circuit thereafter regardless of the operation of the operator. The unit for parallel operation connection of an AC power supply unit according to claim 1, further comprising: