JPH043557Y2 - - Google Patents

Description

[Detailed description of the invention] ``Purpose of the invention'' ``Field of industrial application'' This invention relates to on-board chargers used for electric cars, for example, and in particular, when the power plug is disconnected during the charging period, when the power plug is reconnected, the power plug is removed. This relates to a charger that does not cause arcing or welding due to arcing.

"Prior Art" In general, electric vehicles such as forklifts that use storage batteries as an energy source have used a charger called a quasi-constant voltage type from the viewpoint of economy and maintainability. This type of charger uses a power transformer with split winding of the primary and secondary coils to have some leakage characteristics, and a semiconductor rectifier using silicon diodes to detect the voltage at the turning point during charging. Then, when a preset timer time is reached, an electromagnetic switch installed between the power transformer and the AC power source is cut off, and charging is stopped, using a relatively simple control circuit.

However, with this type of charger, starting and stopping can be done by turning on or stopping the power switch installed between the power supply and the charger.
Since it is only turned OFF, there is no soft start function found in thyristor type chargers, etc. When the charger is started, in addition to the excitation current of the power transformer, there is a rush current to the storage battery due to the differential voltage between the battery nominal voltage and the charger no-load voltage. flows. In the case of electric vehicle chargers, the capacity of the power transformer and the capacity of the storage battery are both large, and the inrush current value also tends to be large (20
(approximately twice as much).

Conventionally, in normal use, the inrush current described above did not pose a problem because the power plug was connected to the outlet while the charger switch was known and the charger switch was then turned on. However, as electric cars have become a familiar part of the general public and are used in all sorts of fields, they are now being used in the same way as small-capacity home appliances, and when the power plug comes off due to someone or a trolley passing by, Cases of people having to re-plug the power plug are becoming more and more noticeable. Particularly in the case of electric cars equipped with on-board chargers, charging can be done anywhere as long as there is an outlet, so the power plug often comes off.

In this case, when the discoverer hurriedly re-inserted the power plug, there was a risk of arcing or welding between the plug-in power plug and the outlet due to inrush current flowing during the plug-in process as charging was in progress.

``Problem that the invention attempts to solve'' The purpose of the invention is to provide a quasi-constant voltage current-limiting function that will restart the battery just by connecting the power plug if the power plug is accidentally unplugged during charging. The purpose is to prevent arcing and welding caused by arcs that occur between the power plug and the outlet due to inrush current when the power plug is reconnected in a vehicle-mounted charger that does not have one.

"Structure of the invention" The structure of this invention will be explained below using diagrams.
In FIG. 1, the charger is connected to an AC power source 12 via a power connector 11. In FIG. Power connector 1
1 is an electromagnetic switch 13 and a thermal switch 14
It is connected to the charging circuit 15 through. AC power supply 1
The AC power of 2 is supplied to a rectifier 17 via a transformer 16, and is outputted to a storage battery 19 through a fuse 18 as a charging current.

Charging is started by connecting the power connector 11 and setting the time by pressing the mechanical timer 20. In a mechanical timer, when the time is set, contact 20a turns on, and when the time is up, the contact turns on.
It becomes OFF. Drive coil 2 of electromagnetic switch 13
3 operates only when both the timer contact 20a and the contact 21a of the ON delay relay 21 are ON, and the electromagnetic switch 13 is turned ON to perform charging.

Now consider the case where the power connector is accidentally disconnected while charging. The mechanical timer 20 closes the contact 2 when the battery voltage detector 22 reaches the turning point voltage.
2a closes, the motor operates and rotates in the time-up direction, and when the dial reaches the OFF position at 0 hours, the timer contact 20a is opened to stop charging and control the push-in time of charging. Therefore, the contact 20a is always closed before the dial reaches the 0 hour position. If the conventional ON delay relay contact 21a is not provided, the electromagnetic switch 13 will be turned on at the same time as the power supply 12 is connected, and charging will begin even before the connection of the power supply connector is sufficiently secure. For this reason, the excitation current and charging inrush current of the power transformer flow while the contacts of the power connector are moving, and there is a risk of arcing if the connection is not made quickly. The circuit of the present invention solves the above problem by using an ON delay relay 21 that turns on the contact 21a after a certain period of time, which is sufficient to reliably connect the connector, after AC power is supplied.

``Effects of the invention'' As described above, according to the invention, if the power plug is accidentally unplugged, it is possible to avoid the occurrence of arcing due to the inrush current when the power plug is plugged in again, which has a safety effect. expensive.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one implementation of the present invention. 11...Power connector, 12...Power supply, 13...
...Electromagnetic switch, 14... Drive coil (electromagnetic switch), 15... Charging circuit, 20... Mechanical timer, 20a... Timer contact, 21... ON day relay, 21a... Contact (ON day relay), 22... ...Battery voltage detector, 22a...Contact (battery voltage detector).

Claims (1)

[Scope of utility model registration request] In an on-vehicle charger, typically a semi-constant voltage type without a current limiting function, which operates immediately when the connection to the power source is interrupted during charging and then reconnected, it is used for a predetermined period of time after being connected to the power source. An automatic charger characterized in that it is provided with a delay means that starts operation after a period of time has elapsed.