Automatic voltage conversion module

Details Automatic voltage conversion module Automatic voltage conversion module

2000-06-01

2001-05-22

Berhane, Adolf Doneke (Department: 2838)

Electric power conversion systems

Current conversion

With means to connect the input to diverse power sources

Reexamination Certificate

active

06236584

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automatic voltage conversion module, and more particularly, to an automatic voltage conversion module, in which a voltage of a utility power supplied to electric or electronic appliances, such as a washing machine, is changed to a voltage which can operate the appliances regardless of conditions of the utility power.
2. Background of the Related Art
In general, since either 110V or 220V AC voltage is supplied to each home, an electric part of home use electric/electronic appliance should be designed for both of the voltages. If an AC 220V should be supplied to a system designed for AC 110V, the system will be damaged, and, if an AC 110V should be supplied to a system designed for AC 221V, the system does not operate properly. Because of the above reason, a change over switch is provided to the electric part, so that the user can match to a supplied voltage for a normal operation of the appliance. However, if the user mismatches the change over switch from overlooking, the foregoing malfunction of the appliance will occur. Therefore, a device is needed that can sense an incoming voltage, and make an automatic change over.
FIG. 1
illustrates a circuit of an electric part used for a related art washing machine. As respective modules in the washing machine are designed for DC 311V, the electric part should change the voltage before supply to the modules.
Referring to
FIG. 1
, the electric part is provided with a utility power source
1
, a power switch
2
for supplying or cutting off the power to a system depending on a users selection, a bridge rectifier
3
for rectifying an AC current from the utility power
1
into a DC current, a smoother
4
having smoothing capacitors C
1
and C
2
and resistors R
1
and R
2
for smoothing the rectified current at the bridge rectifier
3
to provide a 311V DC voltage, and a motor driver
5
for receiving an output of the smoother
4
and driving a washing motor in the washing machine. The smoother
4
has two identical capacitors C
1
and C
2
connected in series, and two identical resistors R
1
and R
2
connected to the capacitors C
1
and C
2
in parallel, respectively.
The operation of the aforementioned related art electric part will be explained.
When the user turns on the power switch
2
for putting the washing machine into operation, the 220V AC power from the utility power source
1
is provided to the bridge rectifier
3
. The bridge rectifier
3
rectifies a current as paths of the current alternates for a positive half cycle and a negative half cycle, and the rectified current is provided to the smoother
4
, where the current is smoothed through the smoothing capacitors C
1
and C
2
, to provide a DC current. In this instance, the smoothed DC current has a voltage of {square root over (2)}·220=311V. During the positive half cycle in the above operation, a closed circuit is formed in an order of the utility power source
1
→the first diode D
1
→the first capacitor C
1
→the second capacitor C
2
→the third diode D
3
→the utility power source
1
. And, during the negative half cycle in the above operation, a closed circuit is formed in an order of the utility power source
1
→the fourth diode D
4
→the first capacitor C
1
→the second capacitor C
2
→the second diode D
2
→the utility power source
1
. At the end, since the DC 311V is charged to the first capacitor C
1
and the second capacitor C
2
continuously, to supply the DC 311V to the motor driver
5
continuously, the washing motor(not shown) can make a regular operation.
However, if a 110V is supplied to the utility power source
1
in the related art electric part, the system can not be operate properly. That is, since the electric part is designed to provide the 311V only when an AC 220V is supplied, in a case when 110V is supplied to the electric part, to provide a DC voltage of {square root over (2)}·110=155.5V through the smoother
4
, the system does not operate properly. If a change over switch is provided for solving the above problem, a separate circuit for changing an external low voltage to a high voltage before supply to the system is required.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an automatic voltage conversion module that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an automatic voltage conversion module, in which a voltage of a utility power is sensed, changed into a voltage required for a system automatically and supplied to the system, for smooth and regular operation of the system.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the automatic voltage conversion module includes a rectifier for receiving and rectifying a utility AC power, a smoother for smoothing a voltage rectified at the rectifier, a voltage sensor for sensing the voltage from the smoother to determine an amplitude of a supplied power, and a smoothing operation selector for changing operation paths of the rectifier according to result of the determination at the voltage senor.
The smoother includes a first, and a second capacitors of the same capacitances connected in series, and the smoothing operation selector includes a switching device connected between a common contact point of the first and the second capacitors and an output terminal on the rectifier.
The voltage sensor includes a third and a fourth voltage dividing resistors connected in series for dividing the voltage from the smoother, and a microcomputer for comparing the divided voltage from the third and fourth voltage dividing resistors to a reference voltage, to determine an amplitude of the utility power, to fix operation of the smoothing operation selector according to the amplitude of the utility power.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 5138547 (1992-08-01), Swoboda
patent: 5572415 (1996-11-01), Mohan
patent: 5793626 (1998-08-01), Jiang
patent: 5831846 (1998-11-01), Jiang

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