JPH049984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a DC power supply device for a vehicle refrigerator;
In particular, by using a drive power source that matches the resonant frequency of a vibrating compressor, when the DC applied voltage of the drive power generation unit that drives the compressor falls below a predetermined voltage, the temperature setting inside the refrigerator is maintained. The present invention relates to a DC power supply device for a vehicle-mounted refrigerator that uses a DC power relay used in a vehicle to cut off the supply of DC power to a drive power generation section.

[Conventional technology]

There is a refrigerator that compresses and liquefies a gaseous refrigerant using a vibrating compressor, and performs cooling etc. using the heat of vaporization when the liquefied refrigerant evaporates. Conventionally,
As an example of a vibrating compressor drive control system used in the refrigerator, there is a system as shown in FIG. The vibrating compressor 5 shown in FIG. 5 connects the DC power source V to the primary windings of the transformer 4 with different polarities by alternately switching the switching transistors TR ₁ and TR ₂ into conduction state. is applied alternately, and the drive is controlled so that a resonance state, that is, maximum efficiency is obtained. At this time, the switching transistors TR ₁ and TR ₂
is alternately switched between a conducting state and a non-conducting state in a manner such as the current waveform shown in FIG. 6, for example, and the switching frequency is controlled to match the resonant frequency of the vibrating compressor 5. To be more specific, in order to switch the collector current “I _c ” in FIG. 6,
A base current "I _B " is alternately supplied from the drive circuit 1-3 to the bases of the switching transistors TR ₁ and TR ₂ . That is, the base current “I _B ”
By supplying a so-called trapezoidal waveform as shown in Figures 1 to 3 as a current waveform obtained by multiplying the current amplification factor "h _FE ", I _c ≧ h _FE × at positions such as points P ₁ to P ₃ in the figure, respectively. By providing the condition _1B , the switching transistors TR ₁ and TR ₂ are alternately switched between a conductive state and a non-conductive state to obtain a driving power source of a desired frequency. Conventionally, as explained above, the vibrating compressor 5 has been driven using a drive power source that matches the resonant frequency of the compressor 5.

In this way, in the drive power generation unit that supplies the drive power that matches the resonant frequency of the vibrating compressor 5, the DC voltage of the DC power supplied to the drive power generation unit, especially the battery power supply, decreases. At that time, the car's refrigerator was turned off to protect the battery.

Figure 7 shows an example of the configuration of a conventional DC power supply device for an on-vehicle refrigerator.
A battery monitor device 92 for monitoring battery voltage was used between the drive power generator 1 and the drive power source generator 31. Inside the battery monitor device 92, the input battery voltage is constantly detected.
When the battery voltage falls below a predetermined voltage, a battery monitor signal is output, and a relay 93 provided in the battery monitor device 92 outputs a battery monitor signal.
When the battery voltage falls below a certain voltage, the supply of DC power to the drive power generation section 31 is stopped.

(Problem to be Solved by the Invention) When the battery voltage that supplies DC power to the drive power generation section falls below a certain voltage, the DC power supply to the drive power generation section is turned off to protect the battery. Although the power supply is stopped, the drive power generation section of a vehicle refrigerator that uses the temperature field back method is equipped with a circuit system that supplies and cuts off DC power within the drive power generation section, so the battery voltage When the voltage drops below a certain voltage, it is desirable that the circuit system described above stops supplying the DC power to the drive power generation section.

The present invention has been made in view of the above points, and when the battery voltage that supplies DC power to the drive power generation section drops to a predetermined voltage, the battery monitor signal output from the battery monitor device is Based on the above, an object of the present invention is to provide a DC power supply device for an on-vehicle refrigerator configured to stop the supply of DC power to a drive power generation unit via a DC power supply/cutoff circuit system provided in the drive power generation unit. It is said that

(Means for Solving the Problems) Therefore, the DC power supply device for an on-vehicle refrigerator of the present invention uses a compressor drive control method that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load. The drive power generation unit includes a drive power generation unit that generates drive power at a predetermined frequency, and the drive power generation unit includes a DC power relay that supplies DC power, and a contact point of the DC power relay that turns off when AC power is applied. The DC power off circuit compares the detected temperature detected by the suction refrigerant temperature detector with the preset temperature inside the refrigerator, and the detection temperature detected by the suction refrigerant temperature detector is compared with the preset temperature inside the refrigerator. and an evaporator temperature comparator that outputs a power-off signal that turns off the contacts of the DC power relay via the DC power-off circuit when the temperature becomes lower than the set temperature of the evaporator. The compressor drive control device drives the compressor using a drive power generated by a drive power source, and when the battery voltage of the DC power supply applied to the drive power generation section becomes lower than a predetermined voltage, The evaporator temperature comparator receives the battery monitor signal output from the battery monitor device and outputs a power off signal, and when the battery voltage falls below a predetermined voltage, DC power is supplied to the drive power generator. It is characterized by stopping the supply of

(Example) This will be explained below with reference to the drawings.

FIG. 1 shows the configuration of a specific embodiment of the present invention, and FIG.
The figure is a conceptual explanatory diagram of the present invention, FIG. 3 is a schematic configuration diagram of a vehicle-mounted refrigerator in which the present invention is used, and FIG. 4 is a circuit diagram of an embodiment of a vehicle-mounted refrigerator in which the present invention is used. .

Before explaining the DC power supply device for a vehicle-mounted refrigerator according to the present invention, the outline of the vehicle-mounted refrigerator to which the present invention is applied and the circuit configuration in which the present invention is used will be described.

In FIG. 3, 1 is a control circuit, 1-1 is a temperature detection section, 1-2 is a calculation section, 1-3 is a drive circuit, 2 and 3 are temperature detectors, 4 is a transformer, 5 is a compressor, 6 is a condenser, 7 is a pressure reducer, 8 is a refrigerator, 8-
1 represents an evaporator.

In the figure, the control circuit 1 is composed of a temperature detection section 1-1, a calculation section, and a drive circuit 1-3, and is used to detect the temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor 5. Based on the respective signals from the detector (T _s ) 2 and the temperature detector (T _d ) 3 that detects the temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor 5, the compressor This is for supplying a drive signal of such a frequency that 5 is driven in a resonant state. Note that the temperature detected by the temperature detection section 1-1 can be considered to be a temperature that substantially corresponds to the pressure of the refrigerant on the suction side and the pressure of the refrigerant on the discharge side.

The vibrating compressor 5, supplied with drive power generated by the drive signal supplied from the control circuit 1, compresses the refrigerant and supplies a mixture of gas and liquid to the condenser 6. It releases heat and liquefies it. Then, the liquefied refrigerant passes through the pressure reducer 7 and is vaporized in the evaporator 8-1 provided in the refrigerator 8, and removes the heat of vaporization.
It is for cooling. The refrigerant that has absorbed the heat of vaporization is compressed again by the compressor 5. By repeating the above closed cycle, the heat removed from the evaporator 8-1 is released from the condenser 6 in the form of heat. The operation of the control circuit 1 will be described in detail below.

In the figure, a temperature detection section 1-1 is for converting signals detected by temperature detectors (eg, thermistors) 2 and 3 into predetermined electrical signals.

In the figure, the calculation section 1-2 causes the compressor 5 to resonate based on the "temperature corresponding to the suction pressure" and "temperature corresponding to the discharge pressure" converted into electrical signals by the temperature detection section 1-1. The purpose is to generate a voltage corresponding to the frequency of driving in the state. and,
The drive circuit 1-3 supplies a drive signal with a frequency corresponding to the voltage supplied from the arithmetic unit 1-2 to the transistors _TR1 and _TR2 in the figure, and connects the DC power supply _Vcc to the transistor 1 of the transformer 4. This is for supplying current to the next winding in the form of a so-called rectangular wave in which the polarity is alternately switched to the windings having different polarities. The AC voltage obtained from the secondary winding of the transformer 4 is supplied to the compressor 5, and the compressor 5 is always driven in a resonant state, that is, driven at maximum efficiency.

In the configuration of an embodiment of a vehicle refrigerator in which the present invention is used as shown in FIG. 4, the symbols 1-1, 1-2,
1-3, 2 to 5, TR ₁ and TR ₂ are the same as those in FIG. 3, so their explanation will be omitted.

9 is a thermo device, 10 is an evaporator temperature comparator, 11 is a transformer, 12 is an AC detector, 1
3 is a surge absorption circuit, 14 is an eddy current detection circuit, 1
5 and 16 are relays, 17 and 18 are AND circuits, 1
9, 20 are OR circuits, 21 is an inverter, 22,
23 represents a diode, 24 represents a volume, and 25 represents a shunt.

The thermo device 9 is for setting the indoor temperature of the refrigerator, and the indoor temperature of the refrigerator is changed according to the setting of the volume 24 provided in the thermo device 9.

The evaporator temperature comparator 10 electrically compares the indoor temperature of the refrigerator set by the volume 24 and the signal from the temperature detector 2 which detects the temperature of the evaporator 8-1, and When the set temperature on the evaporator 8-1 side becomes higher than the temperature on the evaporator 8-1 side, a logic "L" is output. The output of the logic "L" is an OR circuit 2 with a negative input terminal.
0 to the drive circuit 1-3, and turns off the contact of the relay 16 via the AND circuit _{17 .}
Cut off the DC power supply to the

The transformer 11 is for detecting when the in-vehicle refrigerator is connected to a commercial power source, and drops the voltage of the commercial power source. Supply voltage.

The AC detector 12 detects whether or not commercial power is input, and outputs a logic "H" when the commercial power is input. The logic "H" serves as a stop signal to the drive circuit 1-3 via the OR circuit 20, and also turns off the contact of the relay 16 via the AND circuit 17.
through transformer 4, i.e. transistor
Cut off the DC power supply to TR ₁ and TR ₂ . Further, the contact of the relay 15 is turned on via the AND circuit 18, and AC power is supplied to the transformer 4 via the relay 15.

The surge absorption circuit 13 absorbs the surge voltage of the input DC power supply and supplies the DC power to the drive circuit 1-3, and also outputs a logic "H" when the voltage of the input DC power supply is higher than a predetermined voltage. " is output. The logic "H" is applied to the drive circuits 1-3 via the OR circuit 19 to the transistors TR ₁ and TR _2.
The output of the compressor 5 is controlled, and the stroke of the compressor 5 is controlled.

The eddy current detection circuit 14 detects the eddy current flowing through the transistors TR ₁ and TR ₂ together with the shunt 25. When the eddy current detection circuit 14 detects an eddy current, it detects the eddy current flowing through the transistors TR 1 and TR 2 for the drive circuit 1-3.
It outputs an output off latch signal that stops the operation of TR ₁ and TR ₂ to prevent damage to transistors TR ₁ and TR ₂ , etc.

Next, the present invention will be explained in detail using FIGS. 1 and 2.

In Figures 1 and 2, symbols 4, 5, TR ₁ ,
TR ₂ corresponds to the one in FIG. 3 already explained, and the symbols 10 to 12, 15 to 18, and 21 correspond to those in FIG. 4. Reference numeral 31 represents a drive power generation section, 61 represents a battery monitor device, 62 represents a DC power off circuit, and 63 represents a battery.

The DC power off circuit 62 is composed of an AND circuit 17 and an inverter 21, and the logic "L" of the AC detector 12 is input to the inverter 21 unless the AC power is used. Then, the inverter 21 changes the logic to "H" and inputs it to the AND circuit 17. One input terminal of the AND circuit 17 is connected to the output terminal of the evaporator temperature comparator 10.
The DC power relay 16 is energized by the output of 0.
Deactivated. That is, evaporator temperature comparator 1
When the output of 0 is logic "H", the DC power relay 16 is energized via the DC power off circuit 62, and the switching transistors TR ₁ and TR are activated via the DC power transformer 4 of the battery 63. Supplied to ₂ . Further, when the output of the evaporator temperature comparator 10 is logic "L", the DC power supply relay 16 is deenergized by the DC power supply off circuit 62, and the battery 63 to the switching transistors TR ₁ and TR ₂ is turned off.
At the same time, the signal Q from the drive circuit 1-3 is stopped, and the transistors TR ₁ and TR ₂ are turned off.

The battery monitor device 61 monitors the power supply voltage from the battery 63 supplied to the battery monitor device, and when the power supply voltage of the battery 63 falls below a predetermined voltage, the drive power generation unit A battery monitor signal of logic "H" is output to 31. The battery monitor signal is input to the evaporator temperature comparator 10 in the drive power generation section 31.

As mentioned above, the evaporator temperature comparator 10 is
The indoor temperature of the refrigerator set on the thermometer 9 side and the signal from _Ts , that is, the evaporator 8-
When the temperature on the evaporator 8-1 side becomes lower than the indoor set temperature of the refrigerator set on the thermometer 9 side, a logic "L" is output and the DC power supply The DC power supply relay 16 is deenergized via the off circuit 62, and the supply of DC voltage to the switching transistors TR ₁ and TR ₂ is stopped. Also, the evaporator temperature comparator 1
0 is configured to preferentially output a logic "L" power off signal when it receives a battery monitor signal from the battery monitor device 61 indicating that the battery voltage is lower than a certain voltage. As explained above, the logic "L" of the power off signal causes the switching transistor to be activated.
The supply of DC voltage to TR ₁ and TR ₂ is stopped. Also, transistors TR ₁ and TR ₂ are turned off.

〔Effect of the invention〕

As explained above, according to the present invention, the DC power relay used in the drive power generation section is forcibly deenergized by the battery monitor signal from the battery monitor device, so that the drive power is generated. When the DC voltage supplied to the unit, that is, the battery voltage, falls below a predetermined value, the DC power supply relay used in the drive power generation unit stops supplying the DC power voltage, and the battery monitor unit The relay for stopping the DC power supply becomes unnecessary.

[Brief explanation of drawings]

FIG. 1 shows the configuration of a specific embodiment of the present invention, and FIG.
Figure 3 is a conceptual diagram of the present invention, Figure 3 is a schematic configuration diagram of a vehicle refrigerator to which the present invention is applied, Figure 4 is a circuit configuration of an embodiment of a vehicle refrigerator to which the present invention is applied, and Figure 5 6 is an explanatory diagram explaining the conventional compressor drive control method, FIG. 6 is an operation explanatory diagram explaining the operation of the compressor drive control method shown in FIG. 5, and FIG. 7 is a conventional DC power supply for a vehicle refrigerator. An example of the configuration of the device is shown. In the figure, 1 is a control circuit, 1-1 is a temperature detection section, 1
-2 is a calculation unit, 1-3 is a drive circuit, 2 and 3 are temperature detectors, 4 is a transformer, 5 is a compressor, 6 is a condenser, 7 is a pressure reducer, 8 is a refrigerator, and 8-1 is an evaporator , 10 is an evaporator temperature comparator, 16 is a DC power supply relay, 17 is an AND circuit, 21 is an inverter, 31 is a drive power generation section, 61 is a battery monitor device, 62 is a DC power supply off circuit,
TR ₁ and TR ₂ represent transistors.

Claims (1)

[Claims] 1. In a compressor drive control method that drives and controls a vibrating compressor using a predetermined frequency corresponding to the load, a drive power generation section that generates a drive power source of a predetermined frequency is provided, and the drive power generation section includes: A DC power relay that supplies DC power, a DC power off circuit that turns off the contacts of the DC power relay when AC power is applied, and a preset temperature detected by the suction refrigerant temperature detector. When the detected temperature detected by the suction refrigerant temperature detector becomes lower than the preset temperature inside the refrigerator, the DC power supply relay is turned on via the DC power off circuit. and an evaporator temperature comparator that outputs a power off signal to turn off a contact, the compressor drive control device driving the compressor using the drive power generated by the drive power generation section. , when the battery voltage of the DC power supply applied to the drive power generation section falls below a predetermined voltage, the battery monitor device receives a battery monitor signal output from the evaporator temperature comparator and outputs a power off signal. 1. A DC power supply device for an on-vehicle refrigerator, characterized in that the DC power supply device is configured to output DC power, and stops supplying DC power to a drive power generation section when a battery voltage falls below a predetermined voltage.