JPS63309374A - Inverter controlling shape working machine - Google Patents

Abstract

PURPOSE:To facilitate connecting power source of an apparatus and to prevent it from being damaged by forming an input voltage value discrimination circuit to operate by the DC voltage being generated on a primary side rectifier and changing over the connection of transformer wiring via each changeover switch respectively. CONSTITUTION:A couple of input terminals 1 for common use for two kinds of input voltages are connected to the primary side rectifier 2 and the input voltage value discrimination circuit 9 to input the terminal voltage of an inverter circuit 4 is arranged, The output of the inverter circuit 4 is inputted to a main transformer 6 by a first changeover apparatus 5 and supplied from an output terminal 8 to an are load via an rectifier 7. Further, signals from the discrimination circuit 9 are also inputted to second and third changeover apparatuses 10 and 28 and the connection of each transformer wiring is changed over with a control circuit 12 corresponding to the voltage of a power source 1. By this method, since the apparatus is operated only by connecting the apparatus to the input terminals 1 of the power source, the power source connection is facilitated and the apparatus is prevented from being damaged by the erroneous connection.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to inverter-controlled processing machines such as welding machines and cutting machines, and particularly applies to two types of processing machines of different sizes, such as AC IOOV and 200V. [Prior technology] In recent years, small and lightweight portable plasma welding machines and cutting machines have become popular due to the adoption of inverter control, and single-phase 100V
Low input capacity machines are also appearing. However, with a 100V input, the power supply side line current is limited to about 15A due to the capacity of the power supply, so it is not possible to obtain a sufficient output for a welding machine or a cutting machine. Therefore, 100V input is sufficient for simple work such as on-site construction work, but 200V input is sufficient for normal work.
v input is required, and from this, 100v input and 20v input are required.
A device that can also be used as 0V input is desired.

In such a double input voltage type, the same magnitude of output voltage can be obtained from the main transformer and the control circuit transformer for two types of input voltages, and the kVA input can be obtained from each of the two types of input voltage sources. In order to avoid exceeding the kVA capacity, it is necessary to switch the internal circuit according to the magnitude of the input voltage. Conventionally, measures have been taken to deal with this, such as changing the connection of jumper wires built into equipment and using dedicated terminals to which two types of input voltage sources can be connected.

[Problem that the invention seeks to solve]

Double-input voltage type welding and cutting machines such as those mentioned above are small, portable machines that are frequently moved and used, and the power supply connection is often changed, so it is necessary to reconnect jumper wires or use different dedicated terminals each time. It is troublesome to do so, and there is also a high risk of damaging the equipment due to incorrect connections.

In view of the above points, the present invention shares the input terminal to which the power supply is connected for two types of input voltages, and automatically adjusts the magnitude of the input voltage when the device is connected to the power supply and voltage is applied. The purpose is to greatly improve ease of use and eliminate damage to equipment due to incorrect connections by identifying the input voltage value, changing the internal circuit connections and selecting and setting the output current upper limit value according to the input voltage value. shall be.

[Means for solving problems]

In order to achieve the above object, the present invention has a rectifier that directly rectifies AC input on the primary side of a main transformer, and an inverter circuit that uses this rectifier as a DC voltage source, and an inverter control system that controls the output by this inverter circuit. In a processing machine that can be used with two types of input voltages of different magnitudes, there is only one set of input terminals shared by the two types of input voltages, and when a voltage is applied to this input terminal, an input voltage value determination circuit that operates based on the DC voltage generated in the primary rectifier and determines the input voltage value from the magnitude of the DC voltage; and the main transformer and the control circuit transformer for the two types of input voltages. first and second switching devices that switch the connection of the windings of each transformer in accordance with the determination result of the input voltage value determination circuit so that the same magnitude of output voltage is obtained from the processing machine; so that the input does not exceed the kVA capacity of each of the two types of input voltage sources,
a third switch for selecting and setting an upper limit value of the output current of the processing machine by switching an output current value limiting circuit provided in a control circuit that drives the inverter circuit in response to the determination result of the input voltage value determination circuit; It is characterized by having a container.

[For production]

When the input terminal is connected to a power source, before the control circuit is established, an input voltage value determining circuit operates based on the DC voltage generated in the primary rectifier, and determines the input voltage value from the magnitude of the DC voltage. The input voltage value can be determined using, for example, two sets of voltage detection circuits with different operating voltages,
The operating signals of the relays of each voltage detection circuit are the first, second,
The signal is transmitted to the third switch. Then, the connections of the windings of the main transformer and the control circuit transformer are switched by the first and second switching devices, so that the same output voltage can be obtained from each transformer for two types of input voltages. At the same time, the third switch switches the output current value limiting circuit provided in the control circuit that drives the inverter circuit, selects and sets a predetermined upper limit value of the output current corresponding to the input voltage value, and Ensure that the input of the welding machine or cutting machine does not exceed the kVA capacity of each of the two types of input voltage sources.

As described above, it is possible to share the input terminal for two types of input voltages having different magnitudes, and the processing machine operates normally just by connecting the input terminal to the power source.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is an overall circuit block diagram. A primary rectifier 2 is connected to the only input terminal 1 of IMi that is shared for two types of input voltages, and its DC output is smoothed by a capacitor 3. This DC voltage is input to the inverter circuit 4 and converted into high frequency AC. If this inverter circuit section is designed so that it can be used without problems with the higher of the two input voltages, it can also be used for the lower voltage.The AC output of the inverter circuit 4 is connected to the first switch. 5 to the primary side of the main transformer (high frequency transformer) 6,
The secondary output is once again converted into direct current by the rectifier 7 and supplied to an arc load (not shown) from an output terminal 8. The terminal voltage of the capacitor 3 is input to an input voltage value determining circuit 9, and the input voltage value to the input terminal 1 is determined from the magnitude of the DC voltage. Further, this DC voltage also serves as a power source for operating the input voltage value discriminating circuit 9. The input side of a transformer 110 serving as a voltage supply source to the control circuit 12 is connected to the input terminal 1 via the second switch 10 . A signal is transmitted from the input voltage value discrimination circuit 9 to the first switch 5, the second switch 10, and a third switch path, which will be described later, provided in the control circuit 12.

FIG. 2 shows an example of the configuration of the input voltage value discriminating circuit 9. As shown in FIG.

This circuit consists of a constant voltage diode 17, a relay 19 (IY)
It is composed of a first voltage detection circuit including a protection diode 21, and a second voltage detection circuit including a constant voltage diode 16.18, a relay 20 (2Y), and a protection diode η, and the voltage detection circuit of these two sets The terminal voltage of the capacitor 3 or a divided voltage thereof is applied to the circuit. 1st. Second. The third switch 5, 10, 28 is the normally open contact (lYa) of the two sets of relays 19, 20.

2Ya). In the figure,
The input voltage to input terminal 1 is the lower voltage, for example 100
When V, the terminal voltage of the capacitor 3 is blocked by the voltage regulator diode 16, and the relay (2Y) does not operate, and the voltage generated in the voltage regulator diode 17 with the resistors 13 and 14 as limiting resistors is used to control the relay 19. Only (IY) works. At this time, the switching devices 5 and 10 connect the primary winding of the transformer 6.11 to the relay contact I, for example, as shown in FIG.
A circuit is configured that is connected in parallel via Ya. Also, the input voltage to input terminal 1 is the higher voltage, for example 200V.
At this time, the terminal voltage of the capacitor 3 increases proportionally, so this time, with a voltage that sufficiently exceeds the positive voltage of the voltage regulator diode 16, the voltage generated in the voltage regulator diode 18 with the resistor 15 as the limiting resistance, Relay 20 (2Y)
also works. Then, since the normally closed contact 2Yb connected to the relay is opened, the relay 19 (IY) is deactivated. At this time, the primary winding of the transformer 6.11 is connected in series through the relay contact 2 Ya as shown in FIG. 3, and the secondary winding voltage of the transformer 6.11 is the lower input voltage, e.g. It is kept the same as when it was 100v.

This relay 19 or additional operation signal is also transmitted to the control circuit 12 at the same time. FIG. 4 shows a part of the control circuit 12, in which the secondary winding voltage of the transformer 11 is converted to direct current through a rectifier and a smoothing capacitor, and the voltage is stabilized by a limiting resistor 5 and a constant voltage diode. It is supplied as a control source through a control circuit. The output current value of the processing machine is set by a potentiometer n, and the current setting signal is sent to the output current value limiting circuit (limiter) 29 after the third switch.
Alternatively, it is input to the non-inverting input terminal of the operational amplifier 31 via (9). The inverting input terminal of the operational amplifier 31 is connected to a shunt resistor 32 and 1! for constant current control of the output current.
The current feedback signal obtained by detecting the output current is input to the current detection circuit, and the difference signal between this and the current setting signal is sent from the operational amplifier 31 to the pulse width control circuit, and the output pulse signal is used to drive the inverter. It drives the circuit 4 and performs output control.

4 is a circuit that limits the output current value at a lower input voltage, for example, 100V, and (9) is a circuit that limits the output current value by 1ti11 at a higher input voltage, for example, 200V input. The switching device A is connected to the above two sets of output 2 current value limiting circuits by relay contact 1 ``e 2 Ya so that the upper limit value of the output current is increased in advance in accordance with the determination result of the input voltage value. 4, 30 is selectively connected to the current setting signal circuit, for example, in an air plasma cutting machine,
If the output current upper limit value at 200V input is 2OA, 10
When inputting 0V, the output current upper limit value is IOA, 100
v Ensure that the line current of the power supply does not exceed 15A.

An embodiment of the present invention has been described above. After the input voltage value discrimination circuit 9 discriminates the input voltage value when the power is turned on, the relays 19 and 20 are self-held until the power is turned off. It is also effective to prevent the relay from fluttering due to internal voltage fluctuations.

〔Effect of the invention〕

According to the present invention, an input terminal can be shared for two types of input voltages, and the input voltage value is automatically determined to change internal circuit connections and select and set the output current upper limit value.
There is no need to change jumper wire connections or select input terminals according to the input voltage value, and it also eliminates damage to equipment due to incorrect connections. This is particularly effective in making it easier to use small, portable welding and cutting machines that require frequent power supply changes.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram of an embodiment of the present invention, Fig. 2 is a detailed circuit diagram of an input voltage value discrimination circuit, Fig. 3 is a detailed drawing of the transformer connection part, and Fig. 4 is a control diagram. It is a p-thin circuit diagram of a circuit switching part. 1...Input terminal, 2...-order (Flit rectifier, 4
... Inverter circuit, 5... First switching device, 6...
・Main transformer, 7...Secondary side rectifier, 8...Specific force outer element, 9...Input voltage value discrimination circuit, 10...Second switching device, 11...Control 1 circuit transformer, 12... control circuit, 19. Rib...Relay, l Ya, 2 Y
a...Relay contact, n...Potentiometer for output current setting, 4...Third switch, west, 30...Turn on output current setting.

Claims (1)

[Claims] 1. Inverter-controlled processing machines of different sizes have a rectifier that directly rectifies AC input on the primary side of the main transformer, and an inverter circuit that uses this rectifier as a DC voltage source, and the output is controlled by this inverter circuit. In a device that can be used with two types of input voltages, only one set of input terminals is shared for the two types of input voltages, and when a voltage is applied to this input terminal, a direct current is generated in the primary side rectifier. an input voltage value discrimination circuit that operates based on voltage and discriminates the input voltage value from the magnitude of the DC voltage, and an output voltage of the same magnitude from the main transformer and the control circuit transformer for the two types of input voltages. 1. First and second switching devices switch the connection of the windings of each transformer in accordance with the determination result of the input voltage value determination circuit, and the input of the processing machine is set to the two types of input voltages. kVA of each source
In order to avoid exceeding the capacity, an output current value limiting circuit provided in a control circuit that drives the inverter circuit is switched in response to the determination result of the input voltage value determination circuit, and the upper limit value of the output current of the processing machine is set. An inverter-controlled processing machine characterized by being provided with a third switch for selecting and setting.