JPS605754Y2 - capacitor charging circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor charging circuit with improved charging characteristics.

Generally, in equipment that instantaneously supplies energy stored in a capacitor to a load, such as a welding machine or a flash device, the AC input is connected to a rectifier circuit consisting of a pumping capacitor and a diode. A well-known circuit for boost rectification and charging the capacitor is used.

Such a well-known capacitor charging circuit turns off a power switch connected in series with an AC power source to charge the capacitor when the capacitor is not in a state where it can be used as an energy supply source for a load, that is, when it is in an inactive state. The charging voltage is set to zero or a power switch or the like is kept on so that the charging voltage of the capacitor is always maintained at the same potential as in the operating state, that is, the state in which the capacitor can supply a predetermined amount of energy to the load.

However, in the former case, there is a drawback that it takes too much time to boost the voltage when it is necessary to suddenly put it into operation and use it.

This runner-up is particularly significant when the capacitor being charged has a large capacity or when the operating voltage is high.

In the latter case, capacitors generally have a characteristic that their lifespan is shortened if the rated voltage or a voltage close to it is constantly applied, so failures occur frequently.
In particular, when a plurality of capacitors are connected and used, there is a drawback that there is a great risk that destruction of one capacitor will induce destruction of other capacitors.

In view of the above points, an object of the present invention is to provide a capacitor charging circuit that shortens the time it takes for the capacitor to boost its voltage to an operating voltage.

Another object of the invention is to improve capacitor life.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an AC power source.

A power switch 2 and a protective resistor 3 are connected in series to this AC power source 1.

A capacitor 7 is connected in parallel to this series circuit via a first diode 4, a second diode 5, and a third diode 6.

Further, the series circuit of the first diode 4 and the second diode 5 includes a switch element 8 and a first pumping capacitor 9.
The series circuits are connected in parallel.

That is, the first pumping capacitor 9 is connected in series to the capacitor 7 via the third diode 6.

As the switch element 8, not only a mechanical switch but also S
A semiconductor element such as a CR, ) transistor or CDS may also be used.

A second pumping capacitor 10 is connected in parallel to the series circuit of the AC power source 1, the power switch 2, and the protective resistor 3 via the first diode 4.

Furthermore, a load 12 is connected in parallel to the capacitor 7 via a load switch 11, so that energy can be supplied to the load 12.

Next, the operation of the above embodiment will be described.

First, both the power switch 2 and the switch element 8 are turned on.

Since the switch element 8 is on, the capacitor 7 is
By the action of the first pumping capacitor 9 and the second pumping capacitor 10, the highest voltage of the AC power supply 1 is
It can be charged up to twice as much and remain in working condition.

That is, in the case of a welding machine, by turning on the load switch 11, a predetermined amount of energy is passed through the load 12, and the discharge load 12 is sufficiently welded.

Further, if the load uses flash discharge, a predetermined amount of flash can be obtained by turning on the trigger switch of the flash discharge tube and discharging the flash discharge tube.

Next, when only the switch element 8 is turned off to be in an inoperative state, each pumping capacitor 9 and 10 does not perform a pumping action, so the capacitor 7 is charged to the same potential as the AC power supply 1, that is, the voltage 173 in the operating state. be done.

Therefore, the capacitor 7 has a voltage increase of 2/2 to the operating voltage.
3, and the charging time is shortened compared to the conventional method in which the voltage is increased from O(V) by opening and closing only the power switch 2.

Furthermore, since the charging voltage of the capacitor 7 is maintained at a value lower than the operating voltage, its lifespan is significantly extended compared to the case where the operating voltage is constantly applied.

In particular, for electrolytic capacitors, the applied voltage ■≦0.
Since it is said that deterioration is reduced in the range of 7× rated voltage, the life of electrolytic capacitors is significantly improved in equipment such as welding machines and flash devices where electrolytic capacitors are used as capacitors.

Note that when the switch element 8 is turned off, no current from the power supply flows through the first pumping capacitor 9;
Deterioration is reduced.

Further, FIG. 2 shows another embodiment of the present invention, and the same parts as in FIG. 1 are indicated by the same symbols.

That is, this embodiment is an example of 6 times the voltage, and when the power switch 2 and the switch element 8 are both turned on and in the operating state, the capacitors 7 and 13 are connected to the pumping capacitors 9, 10, 14 and 15. Due to this action, the voltage is charged to three times the voltage of the AC power source 1, so that a voltage six times the voltage can be applied to the load 12.

Then, when only the switch element 8 is turned off to be in an inoperable state, each capacitor 7 and 13 is charged to the same potential as the power supply voltage.

Therefore, the time for each capacitor 7 and 13 to increase the voltage in its operating state is shortened compared to when the voltage is increased from OCV), and its lifespan is significantly longer than when the operating voltage is constantly applied. It will be extended.

The present invention is generally suitable for a capacitor charging circuit of 30 times the voltage (n is a positive integer), for example, 2 times the voltage.
It is clear that in a voltage doubler, quadruple voltage, etc. capacitor charging circuit, when the switch element is turned off, the capacitor voltage becomes zero and the boost time is not shortened.

As described above, the present invention is a capacitor charging circuit that can maintain the voltage of the capacitor greater than zero and less than the operating voltage when in the non-operating state, so that the voltage rises to the operating state quickly and the life of the capacitor can be significantly extended. can be obtained.

[Brief explanation of drawings]

1 and 2 show circuit diagrams of an embodiment of the present invention. 1...AC power supply, 2...Power switch, 3...Protection resistor, 4...First diode, 5...Second Diode, 6...
Third diode, 7, 13...Capacitor, 8
......Switch element, 9...First pumping capacitor, 10...Second pumping capacitor, 11...Load switch, 12...
...Negative W, 14,15...Pumping capacitor.

Claims (1)

[Scope of utility model registration request] In devices that charge a capacitor by double-voltage rectification (where n is a natural number) of AC voltage using a pumping capacitor and a diode, a switch element is connected in series with the pumping capacitor that is connected in series with the capacitor. A capacitor charging circuit featuring: