Electric power conversion systems – Current conversion – Including d.c.-a.c.-d.c. converter
Reexamination Certificate
2001-09-21
2002-08-06
Vu, Bao (Department: 2838)
Electric power conversion systems
Current conversion
Including d.c.-a.c.-d.c. converter
C363S022000, C363S097000
Reexamination Certificate
active
06430064
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a non-contact power supply device separately comprising a secondary unit from a primary unit of a coupling transformer for driving a load such as decoration lamps, and more particularly, to a non-contact power supply device which is able to control and change an output voltage of the secondary unit and the load solely from the inside of the premises without need for a user to go outside.
BACKGROUND OF THE INVENTION
There exists a non-contact power supply device capable of separately forming a secondary unit and a primary unit of a coupling transformer. Typically, such a non-contact power supply device is used for driving electric decoration lamps, electric message boards, sign boards, and the like (hereafter “electric decoration” or “load”). A non-contact power supply device, the primary unit is provided inside of a house or building (premises) while the secondary unit is provided at outside. A power plug of the primary unit is plugged into a power socket of an indoor commercial power supply, while the secondary unit is provided outdoor.
Then, both the primary and secondary units of the transformer are arranged to face each other through, for example, a glass window or a wall in between to supply electric power from the inside to the outside, thereby providing electric power to an outside load connected to the secondary unit outside. Thus, in the non-contact power supply device, the indoor commercial power supply can be use for the outdoor load while separating the indoor from the outdoor without needs of opening the door or window.
In the conventional technology, for example, when electric decoration such as decoration lamps (loads) are connected to the secondary unit, a control circuit will be required to change the lighting patterns of the decoration lamps. Thus, such a control circuit is established in the secondary unit connected to the decoration lamps.
However, in the case where the control circuit for changing the lighting patterns of the decoration lamps is provided to the secondary unit, an operation switch for the control circuit also has to be established on the secondary unit. Consequently, the user has to go outside to handle the operation switch, which is inconvenient. In other words, the non-contact power supply device, although being able to use the indoor commercial power supply for the decoration lamps while keeping the premises closed, it involves a problem where the user has to go outside to change the lighting patterns. It is especially troublesome and inconvenient in the winter season, when the non-contact power supply device is used as a power supply for the decoration lights on a Christmas tree.
Further, in the conventional non-contact power supply device, when only a small amount of current (or no current) flows through the secondary unit such as when the load connected thereto is small (or no load), there arises a problem that an output voltage will increase to exceed the allowable level. More specifically, if the load connected to the secondary unit is small such as the control circuit noted above, an excessive voltage will be produced in the secondary unit, which may cause damages in the load.
SUMMARY OF THE INVENTION
Therefore, the present invention is made to solve the problems associated with the non-contact power supply device in the conventional technology mentioned above.
It is an object of the present invention to provide a non-contact power supply device which is capable of controlling an object (load) connected to a secondary unit of a coupling transformer from a primary unit of the coupling transformer without needs for a user to go outside of premises.
It is another object of the present invention to provide a non-contact power supply device which is capable of preventing an output voltage of the secondary unit from becoming excessively large by automatically controlling the output voltage in response to changes in the load connected to the secondary unit.
It is a further object of the present invention to provide a non-contact power supply device which is capable of producing an alternating current (AC) power at outside of the premises which is identical to the commercial AC power supply available inside of the premises.
In one aspect of the present invention, the non-contact power supply device includes a primary unit and a secondary unit of a coupling transformer which are separated from one another in use and transfers electric power from the primary unit to the secondary unit through electromagnetic induction in a non-contact fashion.
In the non-contact power supply device, the secondary unit of the coupling transformer includes a second rectifying smoothing circuit for rectifying and smoothing a high frequency alternating current flowing through a secondary winding based on a high frequency alternating current flowing through a primary winding of the primary unit in order to produce a DC (direct current) output voltage, a voltage hold circuit for maintaining the DC output voltage from the second rectifying smoothing circuit for a predetermined time length, a constant voltage output circuit for producing a stabilized constant voltage based on the DC output voltage from the voltage hold circuit, a control circuit provided with the constant voltage from the constant voltage output circuit for controlling an operation of a load, and a drive signal generation circuit for supplying a drive signal to the control circuit when the output voltage from the second rectifying smoothing circuit becomes smaller than a predetermined voltage.
In the non-contact power supply device, the primary unit of the coupling transformer includes an operation circuit for either stopping the high frequency alternating current flowing through the primary winding or changing the frequency of the high frequency alternating current flowing through the primary winding to decrease the output voltage of the second rectifying smoothing circuit smaller than the predetermined voltage for generating the drive signal by the drive signal generation circuit.
According to the non-contact power supply device of the present invention, the high frequency alternating current flows through the secondary winding of the secondary unit in response to the high frequency alternating current flowing through the primary winding of the primary unit.
The alternating current flowing in the secondary winding is rectified and smoothed by the second rectifying smoothing circuit, and is output as a DC voltage from the second rectifying smoothing circuit.
The output voltage of the second rectifying smoothing circuit is maintained by the voltage hold circuit. Based on the output voltage from the voltage hold circuit, a constant voltage is produced by the constant voltage output circuit. The constant voltage is provided to the control circuit as a power source.
When the alternating current flowing in the primary winding is stopped or its frequency is changed by the operation circuit in the primary unit, the output voltage from the second rectifying smoothing circuit of the secondary unit becomes smaller than the predetermined voltage. As a result, a drive signal is generated from the drive signal output circuit which is provided to the control circuit, thereby changing the load such as lighting patterns of the decoration lamps.
Consequently, a signal for controlling the load can be output to the control circuit in the secondary unit by the operation circuit in the primary unit in the coupling transformer. In other words, the control circuit in the secondary unit can be operated from the primary unit within the premises. Thus, the user can handle the object (load) connected to the secondary unit from the primary unit without needs to go outside of the premises. This is especially useful in the cold season or under bad weather condition.
Further, in the non-contact power supply device, the load is a set of decoration lamps and the control circuit stores a plurality of lighting patterns for the decoration lamps in a memory and changes the lighting pat
Hasegawa Takashi
Ishizaka Hirokazu
Kondou Eiji
Osumi Masuo
Takeuchi Hiroshi
Aichi Electric Co. Ltd.
Muramatsu & Associates
Vu Bao
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