JPS5825019B2 - Energy conservation method for the area of energy conservation - Google Patents

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention relates to a method for injecting energy from a power source into an inductive energy storage device.

When injecting energy into an inductive energy storage device consisting of a reactor having a normal conducting or superconducting coil, a current is supplied to the inductive energy storage device from, for example, a DC power source, and when this current reaches a predetermined value Is, the inductive energy storage device is disconnected from the DC power source and simultaneously short-circuited at both ends.

In this case, the energy storage device has a magnetic energy represented by the following equation, where L is its inductance.

Therefore, the larger the current Is, the more energy can be stored.

However, if the current Is is increased, the capacity of the DC power supply must be increased accordingly.

Generally, a rectifier connected to an AC power supply system is used as this DC power supply, but if a large amount of energy is to be injected into the energy storage device, a rectifier with an extremely large capacity is required.

An object of the present invention is to make it possible to inject a large amount of energy into an energy storage device without increasing the capacity of the power supply significantly.

This object is achieved according to the invention by interposing a capacitor between the power supply and the inductive energy storage device, so that the energy supplied in each case from the power supply to this capacitor is fed into the energy storage device.

In this way, the capacitor is supplied with a small amount of energy each time from the power source, and the energy transferred to the capacitor is injected into the energy storage device, and this operation is repeated each time to increase the current in the energy storage device.

In this case, even if a very large current flows through the energy storage device, only a small current flows through the power supply, which is sufficient to supply a small amount of energy to the capacitor in each case.

The present invention will now be described in more detail with reference to the drawings.

FIG. 1 shows an example of the fundamental configuration of an apparatus for carrying out the method of the present invention.

Reference numeral 1 denotes an inductive energy storage device such as a reactor, to which a flip-wheel diode D1 is connected in parallel.

Reference numeral 2 denotes a rectifier device, for example a silicus, the AC input side of which is connected to a three-phase AC power supply system R, S via a transformer 3.
, T.

A capacitor C is provided between the rectifier 2 and the energy storage device 1.
is involved.

The capacitor C is connected to the energy storage device 1 via a switch S1, and is connected to the DC output terminal of the rectifier 2 via a current-limiting DC reactor DCL.

Next, the energy injection method according to the present invention using the apparatus shown in FIG. 1 will be described.

First, with switch S1 open, the silic rectifier 2
is operated to charge the capacitor C.

When the charging voltage of the capacitor C reaches a preset value VM, the operation of the converter 2 is stopped and a currentless state is established.

Then, the charged energy of the capacitor C is sent to the energy storage device 1 by closing the switch S1.

The capacitor C and the energy storage device 1 then form an LC resonant circuit.

The current in the energy storage device 1 therefore reaches a peak value when the capacitor voltage becomes zero.

When the energy storage current passes its peak point, diode D1 conducts and the energy storage current begins to flow back through this diode.

This causes the capacitor current to go to zero.

Then, after the switch S1 is opened, the capacitor C is charged again by the rectifier 2, and when the charging voltage of the capacitor reaches a preset value VM, the rectifier 2 is blocked and then the switch S1 is closed.

This causes the diode D1 to be non-conductive, forming an oscillatory circuit between the capacitor C and the energy storage device 1, and the energy of the capacitor C is transferred to the energy storage device.

As soon as the voltage across capacitor C passes zero, diode D
When diode 1 becomes conductive, current in the energy storage device begins to circulate through this diode.

By repeating the above operation, a desired amount of energy can be injected into the energy storage device 1.

In this case, the amount of energy supplied from the rectifier 2 to the capacitor C in each case is small, and the extremely large current flowing through the energy storage device 1 does not flow through the rectifier 2, so that a rectifier with a small capacity can be used.

That is, according to the present invention, by interposing a capacitor between the energy storage device and a power source that supplies energy to the energy storage device, it is possible to inject an extremely large amount of energy into the energy storage device with a small power source capacity.

Furthermore, another switch is inserted in series with the diode D1,
If this further switch is opened while switch S1 is closed, the energy of the energy storage device 1 can be returned to the capacitor C.

In this case, the capacitor C is charged with a polarity opposite to that of the energy injection process into the energy storage device 1, so that if the rectifier device 1 is operated in the reverse conversion region, the energy transferred to the capacitor C can be further fed into the AC power supply system.

When energy is supplied from the energy storage device 1 to an AC power supply system, it is preferable to keep the voltage of the capacitor C constant by turning on and off another switch connected in series with the diode.

Of course, if both ends of the capacitor C are connected to a load by another switch, it becomes possible to transfer the energy of the energy storage device 1 to the load.

It goes without saying that the switches in the present invention are not limited to those with contacts, but also include those without contacts such as semiconductor switches.

[Brief description of the drawings]

The figure shows an example of the principle configuration of an apparatus for carrying out the method according to the present invention: 1... energy storage device, 2... rectifier device, C... capacitor, Sl... switch, Dl... diode.

Claims (1)

[Claims] A method of injecting energy into an inductive energy storage device, comprising: a capacitor between an inductive energy storage device consisting of a reactor having a normal conducting or superconducting coil in parallel with a freewheeling diode and a power source having a capacity smaller than the amount of energy to be stored in said device; after a predetermined amount of energy is supplied to said capacitor from the power source, the connection between the power source and the capacitor is substantially cut off; then, by closing a switch provided between the capacitor and the inductive energy storage device, the charging energy of said capacitor is supplied to the inductive energy storage device; when the voltage or current of the capacitor drops to a predetermined value, the switch is opened to supply the predetermined amount of energy from the power source to said capacitor again, and this process is repeated.