JPH0511227B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a power switch device for a vehicle refrigerator;
In particular, in a compressor drive control device that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load, the drive power supplied to the compressor can be turned on/off.
This invention relates to a power switch device for a vehicle-mounted refrigerator in which switching is performed via a control signal line.

(Prior Art) 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. In FIG. 4, the vibrating compressor 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 conductive states. Apply voltage alternately to the line to create a resonant state,
That is, the drive is controlled so as to obtain maximum efficiency.
At this time, the switching transistor TR ₁ ,
TR ₂ is alternately switched between a conductive state and a non-conductive state in a manner such as the current waveform shown in FIG. 5, and the switching frequency is controlled to match the resonant frequency of the vibrating compressor 5. To be more specific, base current "I _B " is alternately supplied from the drive circuit 1-3 to the bases of switching transistors TR ₁ and TR ₂ so that the collector current "I _C " in FIG. 5 is switched. Ru. That is, by supplying a so _- called trapezoidal waveform as _shown in the figures as a current waveform obtained by multiplying the base current "I _B " by the current amplification factor "h _FE ", The switching transistors TR ₁ and TR ₂ are alternately switched into a conductive state and a non-conductive state by providing the following conditions: I _C ≧ h _FE × I _B , respectively, to obtain a driving power source with a desired frequency. There is. 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 conventional car refrigerators that drive the compressor 5 using a drive power source that matches the resonant frequency of the vibrating compressor 5, the power switch that supplies or cuts off power is connected directly to the power line. I was going against it.

(Problem to be solved by the invention) Therefore, the power switch must be installed in a position that is easy to operate from the outside, and the power line wires are routed inside the device, resulting in unnecessary voltage drop and power loss. It was causing a lot of wear and tear. In addition, since the power line is turned on and off, the contacts of the power switch are subject to severe wear, requiring the use of a switch with a large capacity, and since an AC switch is used, one with high withstand voltage must be used. It didn't happen.

The purpose of the present invention is to solve the above problems, and as a power switch for an on-vehicle refrigerator,
Instead of turning the power line on and off, the power generation unit that generates the power supply for the compressor is stopped using the on/off signal from the control signal line,
The object of the present invention is to provide a power switch device for a vehicle-mounted refrigerator in which the power supply voltage can be easily switched via a control signal line.

(Means for Solving the Problems) Therefore, the power switch device for a vehicle-mounted refrigerator of the present invention is a compressor drive control device that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load. A compressor drive control device that includes a drive power generation section that generates a drive power source of a predetermined frequency, and drives the compressor using the drive power generated by the drive power generation section, the drive power source A stop circuit is provided to stop the output Q of the drive circuit that drives and controls the switching element provided in the generator at a predetermined frequency, and the drive power of the drive power generator is controlled by an on/off signal from the stop circuit. The feature is that it can be turned on and off.

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

FIG. 1 shows the configuration of an embodiment of a power switch device for a vehicle refrigerator according to the present invention, FIG. 2 is a schematic diagram of a vehicle refrigerator to which the present invention is applied, and FIG. 3 shows a vehicle refrigerator to which the present invention is applied. 1 shows a circuit configuration of an embodiment of a commercial refrigerator.

Before explaining the power switch 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. 2, 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 includes a temperature detection section 1-1, a calculation section 1-2, and a drive circuit 1-3, and controls the temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor 5. Temperature detector to detect ( _TS )
The compressor 5 is driven in a resonant state based on respective signals from the temperature detector (Td) 3 that detects the temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor 2 and the compressor 5. This is to supply a drive signal with a frequency such that 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 calculation unit 1-2 to the transistors TR ₁ and TR ₂ in the figure, and supplies the DC power supply V _CC 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 circuit configuration of an embodiment of an on-vehicle refrigerator in which the present invention is used, shown in FIG.
2, 1-3, 2 to 5, TR ₁ , and TR ₂ are the same as those in FIG. 2, 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 overcurrent 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 changes depending on the setting of the volume 24 provided in the thermo device 9.

The evaporator temperature comparator 10 electrically compares the indoor temperature signal of the refrigerator set by the volume 24 with 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 ,
The output of TR ₂ is controlled, and the stroke of the compressor 5 is controlled.

The overcurrent detection circuit 14 detects an overcurrent flowing through the transistors TR ₁ and TR ₂ together with the shunt 25. When the overcurrent detection circuit 14 detects an overcurrent, the overcurrent is transmitted to 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 more detail using FIG.

In FIG. 1, the symbols 1-2, 1-3, 4,
5, TR ₁ and TR ₂ correspond to those shown in FIG.
corresponds to that in Fig. 3. Reference numeral 31 represents a drive power generation section, 51 represents a stop circuit, and 52 represents a power switch.

The stop circuit 51 includes an evaporator temperature comparator 10,
It is composed of an OR circuit 20 and a power switch 52, and the logic "H" that the stop circuit 51 outputs to the drive circuit 1-3 causes the drive circuit 1-3 to alternately output at a certain resonance frequency. Output Q, is stopped.

As mentioned above, the evaporator temperature comparator 10 is
The indoor set temperature of the refrigerator set on the thermometer 9 side and the signal from the T _S , 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 A logic "L" is output through the provided AND circuit.
Logic “L” from the evaporator temperature comparator 10
becomes a stop signal to the drive circuit 1-3 via the OR circuit 20, and at the same time serves as a stop signal to the AND circuit 17.
The configuration is such that the relay is turned off via the switch, and the supply of DC voltage to the switching transistors TR ₁ and TR ₂ is stopped.

When the power switch 52 is off, logic “H”
is input to the AND circuit provided in the evaporator temperature comparator 10, and the drive power generation section 31 is turned on and off by a signal from the thermometer 9. Furthermore, when the power switch 52 is turned on, the logic becomes "L".
is input to the AND circuit provided in the evaporator temperature comparator 10. As a result, a logic "L" is output from the AND circuit. That is, the evaporator temperature comparator 10 outputs a logic "L".
The logic "L" is the drive circuit 1- as explained above.
This serves as a stop signal to the switching transistors TR ₁ and TR 2, and also serves to stop the supply of DC voltage to the switching transistors TR 1 and TR ₂ . That is, the supply and cutoff of power to the compressor 5 can be controlled by signals from the control system that turn the power switch 52 on and off.

(Effects of the Invention) As explained above, according to the present invention, the power is supplied and cut off by signals from the control system, so the wires used are thin and have low withstand voltage. Wire routing is simplified.
Furthermore, since the signal is for a control system, a power switch with a small contact capacity can be used, and the power switch can be placed outside the device and placed in a position where it can be easily operated. Then replace the power switch,
It is also possible to replace the signal with a signal from a pressure switch, engine key, etc.

[Brief explanation of the drawing]

FIG. 1 shows the configuration of an embodiment of a power switch device for a vehicle refrigerator according to the present invention, FIG. 2 is a schematic diagram of a vehicle refrigerator to which the present invention is applied, and FIG. 3 shows a vehicle refrigerator to which the present invention is applied. FIG. 4 is an explanatory diagram illustrating a conventional compressor drive control system, and FIG. 5 is an operation explanatory diagram illustrating the operation of the compressor drive control system shown in FIG. 4. There is. 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 relay, 17 is an AND circuit, 19 is an OR circuit, 21
51 represents an inverter, 51 represents a stop circuit, and 52 represents a power switch.

Claims (1)

[Claims] 1. A compressor drive control device that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load, including a drive power generation section that generates a drive power source of a predetermined frequency, and A compressor drive control device that drives the compressor using the drive power generated by the drive circuit, the drive circuit controlling the driving of a switching element provided in the drive power generation section at a predetermined frequency. ，
1. A power switch device for a vehicle-mounted refrigerator, characterized in that a stop circuit is provided for stopping the power supply, and the drive power source of the drive power generation section is turned on and off by an on/off signal from the stop circuit.