JPS6346351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigerator, and particularly to a DC-driven refrigerator configured to charge a battery of a DC power source using a thermostat that switches based on the temperature inside the refrigerator.

There are three types of refrigerators: DC-powered refrigerators that use a car battery as their power source, AC-powered refrigerators that use commercial power as their power source, and AC/DC dual-use refrigerators that can be used with both DC and AC power sources.

DC-powered refrigerators, that is, DC-powered refrigerators, mainly use car batteries as their power source, and therefore have the drawback that over-discharge of the battery is likely to occur, which greatly affects the lifespan of the battery.

Therefore, there is a battery charger that rectifies an AC power source into DC and charges the battery while operating a DC-driven refrigerator with the battery. It has also been practiced to attach a capacitor to the battery charger to provide a smoothed DC power source, and then operate the DC-driven refrigerator using the AC power source.

For example, when a car is running with a DC-powered refrigerator (hereinafter referred to as a refrigerator) installed, the car's battery is the power source, and the battery is used to operate the refrigerator while the car is running. If you come home in the evening and put your car in a garage, etc.
Connect an AC power source (commercial power source) to the AC power terminal provided on the refrigerator, and from this point on, charge the battery with the battery charger described above, and at the same time,
The refrigerator is operated with DC power obtained from the battery charger. In the morning, the refrigerator is cold and the battery is charged.

However, since the battery charger in this case performs both functions of operating the refrigerator and charging the battery at the same time, the battery charger needs to have a large capacity, which makes the battery charger large and heavy. It has the disadvantage of being heavy and expensive.

The present invention aims to solve the above-mentioned drawbacks, and focuses on the operation of the contacts of the thermostat that turns on and off the power supply to the refrigerator, which is installed to control the temperature inside the refrigerator at a constant level. ,
An object of the present invention is to provide a refrigerator equipped with a control circuit that controls the flow of charging current from a battery charger to a battery when a thermostat is turned off and power supply from the battery charger to the refrigerator is stopped. . This will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the configuration of a power supply for a refrigerator according to the present invention, and FIG. 2 shows a specific embodiment of the circuit configuration of the controller used in FIG.

In the figure, numeral 1 is a refrigerator that is driven by a DC power supply, 2 is an AC power supply (commercial power supply) terminal, and 3
is a DC power terminal, 4 is a transformer, 5 and 6 are diodes, 7 is a capacitor, 8 is a thermostat which functions to switch the supply of DC power to the refrigerator 1 or the DC power terminal 3, and 9 is a controller. 10 to control the following relays:
1 and 2 indicate relays that are driven under the control of the controller 9, respectively.

A signal voltage or DC power is input to the controller 9 from one end A of the secondary winding of the transformer 4, the anode connection point B of the diodes 5 and 6, and the anode side C of the DC power supply terminal 3, and the controller 9 is connected to the relay. The ten contacts are controlled as follows.

(1) When a commercial power source is connected to AC power terminal 2 and a battery is connected to DC power terminal 3.

The controller 9 is connected to the relay 1 as shown in FIG.
0 contact is connected to b (this control of the controller 9 is explained in FIG. 2). Therefore, the DC output of the converter smoothed by the diodes 5 and 6 and the capacitor 7 supplies power to the refrigerator 1 via the thermostat 8. When the temperature inside the refrigerator 1 decreases and the thermostat 8 is turned off, that is, when the contact point of the thermostat 8 is connected to d, the DC output is transferred to the relay 10.
The battery connected to the DC power supply terminal 3 is charged through the contact point. When the temperature inside the refrigerator 1 rises and the thermostat 8 operates, that is, when the contact point of the thermostat 8 is connected to c, power is supplied to the refrigerator 1 again. That is, a circuit is constructed in which charging current flows into the battery when the thermostat 8 is turned off.

(2) When a commercial power source is connected to AC power terminal 2 and a battery is not connected to DC power terminal 3.

The controller 9 performs the same control on the relay 10 as in the case (1) above. and refrigerator 1
The power supply to is also the same as in case (1) above.

(3) When a commercial power source is not connected to AC power terminal 2, and a battery with a power supply of a predetermined voltage or higher is connected to DC power terminal 3.

The controller 9 controls the relay 10 so that the contact point of the relay 10 is connected to a. Electric power is supplied to the refrigerator 1 from a battery connected to a DC power terminal 3 via a relay 10 and a thermostat 8. When the temperature inside the refrigerator 1 drops, the thermostat 8 is turned off and the power supply is cut off, and when the temperature inside the refrigerator 1 rises, the thermostat 8 is turned on and power is again supplied from the battery.

(4) When a commercial power source is not connected to AC power terminal 2, and a battery with a voltage lower than the specified voltage is connected to DC power terminal 3.

The controller 9 controls the relay 10 so that the contact point of the relay 10 is connected to b. As a result, power supply to the refrigerator 1 is cut off, and over-discharge of the battery connected to the DC power supply terminal 3 is prevented.

Next, control operations for the relay 10 in each of the above cases will be explained using a specific example circuit configuration of the controller shown in FIG.

In the figure, numerals 9 and 10 correspond to those in Fig. 1,
A, B, and C correspond to each point in FIG. T ₁
or T ₃ are transistors, D ₁ to D ₅ are diodes, D ₆ is a Zener diode, R ₁ is a variable resistor,
R ₂ to R ₇ represent resistors, and C ₁ to C ₄ represent capacitors, respectively.

When a commercial power source is connected to the AC power terminal 2, an AC voltage is generated at one end A of the transformer 4. This alternating voltage is rectified by diode D ₄ ,
After being smoothed by capacitor C ₄ , the base current flows into transistor T ₃ via resistor R ₆ . Accordingly, the transistor _T3 is turned on, and the collector voltage of the transistor _T3 becomes almost zero potential. As a result, the transistor _T2 is turned off, and since the emitter and base of the transistor _T1 are at the same potential, the transistor _T1 is also turned off. That is, relay 1
No current flows through the coil at 0, as shown in Figure 1.
The contact is in a normal state, that is, connected to b. The DC voltage at point B that is input to the controller 9 serves as a power source for the controller 9.

As long as the commercial power source is connected to the AC power terminal 2, the transistor _T3 is turned on even if a battery is connected to the DC power terminal 3, so the relay 10 is deenergized as described above.

Therefore, as explained in (1) and (2), electric power is supplied to the refrigerator 1 via the thermostat 8, and when the thermostat 8 is turned off, the thermostat is supplied to the battery connected to the DC power terminal 3. A charging current flows through the contacts of the relay 8 and the relay 10 to charge the battery.

If a commercial power supply is not connected to AC power supply terminal 2 and a battery is connected to DC power supply terminal 3, the signal voltage at point A does not appear and the transistor
T ₃ is off. Therefore, the voltage applied to the cathode of the Zener diode _D6 is the voltage at point C, that is, the _voltage at the battery _.
This is the voltage generated across the resistor R ₂ that is distributed according to the ratio between the R 2 and the R 2 , and the voltage is varied by the variable resistor R ₁ . When the voltage developed across the resistor R ₂ is higher than the Zener voltage of the Zener diode D ₆ , the transistor T ₂ is turned on, and when it is lower than the Zener voltage of the Zener diode D ₆ , the transistor T ₂ is turned off.

Variable resistor _R1 is set so that when the battery connected to DC power supply terminal 3 is at a predetermined voltage or higher, the voltage generated across resistor _R2 is higher than the Zener voltage of Zener diode _D6 . and transistor _T2 is on.
When the transistor _T2 is turned on, the base current of the transistor _T1 starts to flow to the ground via the resistor _R4 and the transistor _T2 , and the transistor T2 is turned on.
_T1 is turned on. This energizes the coil of relay 10, and its contacts are connected to a. Thus, as explained in (3) above, a circuit is constructed in which power is supplied from the battery connected to the DC power supply terminal 3 to the refrigerator 1 via the contacts of the relay 10 and thermostat 8.

When the battery connected to the DC power supply terminal 3 is below a predetermined voltage, the voltage generated across the resistor 2 is lower than the Zener voltage of the Zener diode _D6 , and the transistor _T2 is turned off.
Transistor _T1 is then turned off as explained above, and relay 10 is deenergized, with its contacts in the position connected to b as shown in FIG.
As a result, the supply of power to the refrigerator 1 from the low-voltage battery connected to the DC power supply terminal 3 is cut off, and over-discharge of the battery is avoided.

As explained above, according to the present invention, by using the contacts of the thermostat for controlling the temperature inside the refrigerator and by providing a control circuit for a controller and a relay controlled by the controller, the refrigerator can be operated using AC power. When the thermostat is turned off while driving, the battery connected to the DC power terminal can be charged. Since the battery is charged when the refrigerator is not operating, the AC/DC converter is shared.
Its capacity is small, and as a result, refrigerators become smaller and lighter in weight, leading to lower prices.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the configuration of a power supply for a refrigerator according to the present invention, and FIG. 2 shows a specific embodiment of the circuit configuration of the controller used in FIG. In the figure, 1 is a refrigerator, 2 is an AC power terminal, 3 is a DC power terminal, 4 is a transformer, 5 and 6 are diodes, 7 is a capacitor, 8 is a thermostat, 9 is a controller, and 10 is a relay. .

Claims (1)

[Claims] 1 It is equipped with a converter that converts alternating current into direct current, and is also equipped with a direct current power terminal to which a battery is connected, and the supply of direct current power is performed by switching the on contact and off contact of the thermostat, which operates based on the temperature inside the refrigerator. In the controlled DC-driven refrigerator, the presence or absence of the AC power supply voltage and the presence or absence of the DC power supply voltage are checked, and while the AC power supply voltage is present at least, the power supply end from the DC power supply is switched to the first one. A controller is provided for switching from a state of connection to a contact to a state of connection to a second contact, and is configured to connect an output end of the converter to a common terminal of the thermostat, and is switched by the controller. A refrigerator characterized in that a first contact is connected to a common terminal of the thermostat, and a second contact switched by the controller is connected to an off contact of the thermostat.