JP2563757Y2 - Welding machine charging equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for a welding machine in which a shunt resistor is connected between a switching element for controlling a welding current and a ground.

[0002]

2. Description of the Related Art Conventionally, a power source of a direct welding machine supplies power to a welding circuit in a configuration shown in FIG.
1 and prevention of overvoltage input of the power supply.

The AC power supply 12 is a no-fuse breaker 1
3, a voltage supplied to the primary side of the transformer 15 via the relay 14 and generated on the secondary side thereof is applied to diodes 16 and 17;
To charge the battery 11 and supply DC power to the welding circuit.

When charging a battery, it is necessary to perform trickle charging even after the specified voltage is reached in order to stabilize the specific gravity of the battery fluid.
5, the number of turns on the primary side is switched, the output voltage on the secondary side is lowered, and trickle charging is performed for a predetermined period by a timer or the like.

For overvoltage of the AC power supply 12, a no-fuse breaker 13 also serving as a main switch is inserted into the primary side of the transformer 15 so that a battery such as when a 100V power supply is erroneously connected to a 200V power supply. 11, the transformer 15, the diodes 16, 17 and the like are prevented from being damaged.

[0006]

In a conventional battery charging method in which the primary winding number of the transformer 15 is switched by using the relay 14 to perform trickle charging, the relay 14 is used.
Of the transformer 15
However, there is a disadvantage that the price is increased due to the removal of the intermediate tap on the primary side.

In the method of preventing overvoltage input using the no-fuse breaker 13 also serving as a main switch, it takes a certain time before the no-fuse breaker 13 operates, and furthermore, after the operation, the user may notice the overvoltage input. However, if the no-fuse breaker 13 is replaced many times, parts such as the transformer 15, the diodes 16, 17 are damaged.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks. The present invention is directed to a welding machine capable of performing trickle charging without switching the tap of a transformer, and immediately shutting off the input of the overvoltage even if there is an overvoltage input. It is intended to provide a charging device.

[0009]

To achieve the above object, a charging device for a welding machine according to the present invention comprises a switching element (3) for turning on and off a voltage of a power supply (1) having one electrode grounded; Reactor (2) and shunt resistor (4)
When the power switch inserted between the battery (11) and the charge control circuit (9) is turned on, the charging of the battery (11) in the power supply (1) is started, and first battery but to carry out the normal battery charging when: predetermined voltage, when it is more than the voltage the battery voltage is predetermined to perform a predetermined period trickle since then
Charging means and shunt resistance when welding is taking place
The welding current pulse flowing through (4) is detected, and the welding current pulse is detected.
A second method for performing the normal battery charging based on the pulse
A charge control circuit (9) including battery charging means is provided to charge the battery.

[0010]

FIG. 1 shows an embodiment of the present invention.
1 is a power supply, 2 is a reactor, 3 is a switching element,
4 is a shunt resistor, 6 is a weld, 7 is a commutation diode,
Reference numeral 8 denotes a noise removal amplifier, 9 denotes a charge control circuit, and 10 denotes an overvoltage input prevention circuit.

A shunt resistor 4 is connected between a switching element (a transistor will be described as an example in the following embodiment) 3 and the ground. When the transistor 3 is turned on by a PWM control signal, the shunt resistor 4 flows to the reactor 2. A welding current flows through the shunt resistor 4. That is, when the transistor 3 is turned on, a welding current flows in the circuit of the power source 1, the reactor 2, the welding portion 6, the transistor 3, the shunt resistor 4, the ground and the power source 1, and the transistor 3 is turned on from the shunt resistor 4. A welding current is detected.

When the transistor 3 is turned off, a welding current flows in the circuit of the reactor 2, the welding portion 6, the commutation diode 7, and the reactor 2 due to the energy stored in the reactor 2, and the arc is extinguished in the welding portion 6. Is prevented.

Battery 11 and charge control circuit 9
By turning on a power switch inserted between the battery and the battery, charging of the battery in the power supply 1 is started, and normal battery charging is performed when the battery voltage is equal to or lower than a predetermined voltage. When the voltage exceeds the voltage, trickle charge is performed for a predetermined period from that time. Further, while the welding current is flowing through the shunt resistor 4, the charge control circuit 9 detects this current via the noise elimination amplifier 8, and performs normal battery charging. A specific circuit configuration of the charge control circuit 9 is shown in FIG.

When an AC voltage higher than a specified value is erroneously applied to the power supply 1, the overvoltage input prevention circuit 10 detects the application of the AC voltage higher than the specified value, and immediately shuts off the application of the AC voltage. We are protecting. The specific circuit configuration of the overvoltage input prevention circuit 10 is shown in FIG.

FIG. 2 shows an embodiment of the power supply.
In the figure, reference numerals 1 and 11 correspond to those in FIG.
3, 15 to 17 correspond to those in FIG.

Reference numeral 18 represents a detection transformer, 19 represents a triac, 20 represents a photocoupler, 21 and 22 represent transistors, 23 represents a rectifier, 24 and 25 represent diodes, 26 represents a capacitor, and 27 to 32 represent resistors.

During welding, the transistor 22
Is turned off, the transistor 21 is turned on, and the triac 19 is controlled to be always on via the photocoupler 20. The AC voltage generated on the secondary side of the transformer 15 is rectified by the diodes 16 and 17, and the battery 11 is charged. It is supposed to.

Trickle charging, which is performed when the battery voltage becomes equal to or higher than a predetermined voltage, turns on / off the transistor 21 based on the voltage synchronized with the AC power supply 12 using the transformer 18 and the rectifier 23 and turns the photocoupler 20 on. This is performed by controlling the switching of the triac 19 through the switch.

FIG. 3 shows a configuration of an embodiment of a noise removal amplification and charge control circuit.
9 corresponds to that of FIG. Reference numerals 33 to 35,
37 is a comparator, 36 is an amplifier, 38 is a buffer
An amplifier, 39 is a timer circuit, 40 and 41 are flip-flop circuits, 42 to 47 and 78 are diodes, 48 to 50 are capacitors, 51 is a variable resistor, and 52 to 6
5 represents a resistor.

When welding is being performed, the shunt resistance 4
Generates a pulse having a wave height proportional to the magnitude of the welding current in accordance with the switching of the transistor 3. After the noise component of this pulse is removed by a filter of a resistor 52 and a capacitor 48, the welding current pulse is appropriately amplified by an amplifier 36 and input to a comparator 33.

When welding is being performed, the pulse of the welding current input to the comparator 33 is much larger than the forward voltage drop of the diode 78 of the reference voltage. Is output. This pulse is applied to the flip-flop circuit 40,
41 are reset, and the output Q of the flip-flop circuit 40 is at L level,
H level is output to the output Q bar.

The L level output from the flip-flop circuit 40 is input to an AND circuit composed of diodes 45 and 46 and a resistor 64 to prevent a control pulse for trickle charging generated from the comparator 37 from passing therethrough. , The L level is output from the buffer amplifier 38. The L level of the buffer amplifier 38 turns off the transistor 22 via the diode 24 and the resistor 32.

The H level output from the flip-flop circuit 41 turns on the transistor 21 via the resistor 27. Therefore, as described with reference to FIG. 2, the triac 19 is controlled to be always on, and the battery 11 is normally charged.

The DC voltage obtained by stepping down the AC power supply 12 by the transformer 18 and full-wave rectified by the rectifier 23 is further divided by the resistors 58 and 59 in the charge control circuit 9 and inputted to the comparator 35 to be inputted to the diode 42. This is compared with the forward voltage drop. A rectangular wave synchronized with the power supply voltage waveform of the AC power supply 12 is obtained from the comparator 35 as shown in FIG. The comparator 35 and the diode 4
3, 44, the resistors 62, 63, and the capacitor 49 constitute a saw-tooth wave generating circuit.
, A sawtooth wave synchronized with the power supply voltage waveform is input and compared with a reference voltage K set by the variable resistor 51. Accordingly, the control pulse for trickle charging shown in FIG. 4 is generated from the comparator 37.

As will be described below, when the battery 11 is charged to a voltage equal to or higher than a predetermined voltage, the diode 46 is reverse-biased, and the charge control circuit 9 generates the above-mentioned trickle charge control pulse. The voltage is applied to the transistor 22 in the power supply 1. As a result, a pulse shown in FIG. 4 is generated at the point C of the collector of the transistor 22.

Next, trickle charging will be described with reference to the time chart of FIG. When the voltage of the battery 11 becomes equal to or higher than a predetermined voltage by normal charging, the comparator 34 monitoring the battery voltage sets the flip-flop circuit 40, activates the timer circuit 39, and sets the cathode of the diode 46 to the H level. Apply.

Since the above-described trickle charge control pulse generated from the comparator 37 has the H level applied to the cathode of the diode 46, the diode 4
The charge control circuit 9 passes through an AND circuit including the resistors 5 and 46 and the resistor 64, and is output from the charge control circuit 9 via the buffer amplifier 38. The diode 24 and the resistor 3 in the power supply 1
2 controls the transistor 22.

Therefore, the pulse shown in FIG. 5 is generated at the collector of the transistor 22, and the triac 19 is switched via the photocoupler 20. That is, the phase control of the AC power supply 12 is performed.

As a result, the voltage generated on the secondary side of the transformer 15 drops, the current for charging the battery 11 decreases, and a trickle charge state is entered. This trickle charging current is arbitrarily set by the variable resistor 51.

When a predetermined period has elapsed from the start of trickle charging, an H-level signal is output from the timer circuit 39. This H-level signal is set on the flip-flop circuit 41 via a differentiating circuit of the capacitor 50 and the resistor 65, and the output Q bar is inverted from H level to L level. As a result, the transistor 21 in the power supply 1 is turned off, the operation of the photocoupler 20 is blocked, and the triac 19 stops its switching operation. That is, the trickle charging of the battery 11 ends.

When welding is restarted during trickle charging or after trickle charging is completed, the flip-flop circuits 40 and 41 are reset as described above, the normal charging pressure is restarted, and trickle charging is performed.

FIG. 6 shows an embodiment of the overvoltage input prevention circuit. In the figure, 71 is a comparator, 72 is a buffer amplifier, 73 is a capacitor, 74 is a variable resistor, 7
Reference numerals 5 to 77 represent resistors.

When a high voltage is applied to the AC power supply 12 in the power supply 1, for example, an AC power supply having a rated 100V
When an AC power supply of 0 V is connected, the high voltage of 200 V is rectified by the rectifier 23 through the transformer 18 and
The voltage is divided by (76) and is input to the comparator 71. The comparator 71 compares this input voltage with the reference voltage of the voltage to be cut set by the variable resistor 74, and outputs a signal of H level from the comparator 71.

This H-level signal charges the capacitor 73 and is input to the power supply 1 via the buffer amplifier 72, and turns on the transistor 22 via the diode 25 and the resistor 32. Therefore, the photocoupler 20 is turned off, and the operation of the triac 19 is prevented. That is, the high voltage is cut off by the triac 19 from the negative or positive wave following the positive or negative wave of the AC power supply 12.

The winding specification of the transformer 18 and the rectifier 23 are provided with a sufficient margin against overvoltage. As can be seen from the above description, the no-fuse breaker 13 only functions as a main switch.

[0036]

As described above, according to the present invention, since there is no mechanical contact such as a relay according to the present invention, the reliability is greatly improved, and a variable resistor is used during trickle charging. An optimum current value can be set for the battery, and the transformer does not require a primary intermediate tap, so that the cost is low.

In the case of the second aspect, since the application of the overvoltage is cut off by the electronic circuit, the overcurrent can be cut in a very short time, so that the load on each part is reduced. The cut voltage can be easily set by the variable resistor.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows an embodiment of a power supply.

FIG. 3 shows a configuration of an embodiment of a charge control circuit.

FIG. 4 is an explanatory diagram of a control pulse generation waveform for trickle charging.

FIG. 5 shows a time chart of one embodiment of trickle charging.

FIG. 6 shows a configuration of an embodiment of an overvoltage input prevention circuit.

FIG. 7 shows a power supply configuration of a conventional welding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power supply 2 Reactor 3 Switching element (transistor) 4 Shunt resistor 6 Weld part 7 Commutation diode 8 Noise removal amplification part 9 Charge control circuit 10 Overvoltage input prevention circuit 11 Battery 12 AC power supply 13 No fuse breaker 15 Transformer 16, 17 Diode 19 Triac

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-190524 (JP, A) JP-A-61-139234 (JP, A) JP-A-53-58638 (JP, A) JP-A-61-1986 244233 (JP, A) JP-A-56-25341 (JP, A) JP-A-2-104740 (JP, U) JP-A-61-144746 (JP, U) JP-A-2-68642 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] 1. A welding machine comprising a switching element (3) for turning on and off a voltage of a power supply (1) having one electrode grounded, a reactor (2), and a shunt resistor (4). ) And the charge control circuit (9), the power switch is turned on to start charging the battery (11) in the power supply (1),
First battery charging means for performing normal battery charging when the battery voltage is equal to or lower than a predetermined voltage, and performing trickle charging for a predetermined period when the battery voltage becomes equal to or higher than the predetermined voltage ; Welding done
The welding current flowing through the shunt resistor (4)
Is detected, and the normal
And second battery charging means for performing battery charging.
A charging device for a welding machine, comprising a charge control circuit (9) for charging a battery. 2. A welding machine comprising a switching element (3) for turning on and off a voltage of a power supply (1) having one electrode grounded, a reactor (2), and a shunt resistor (4). ) And the charge control circuit (9), the power switch is turned on to start charging the battery (11) in the power supply (1),
First battery charging means for performing normal battery charging when the battery voltage is equal to or lower than a predetermined voltage, and performing trickle charging for a predetermined period when the battery voltage becomes equal to or higher than the predetermined voltage ; Welding done
The welding current flowing through the shunt resistor (4)
Is detected, and the normal
And second battery charging means for performing battery charging.
A charge control circuit (9) is provided, and an overvoltage input prevention circuit (10) for shutting off the overvoltage when an overvoltage AC voltage is applied to the power supply (1) is provided to protect the power supply (1). A charging device for a welding machine, comprising: