JPH0557502B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an on-vehicle refrigerator device, particularly a compressor drive control device that controls the drive of a vibrating compressor using a predetermined frequency corresponding to a load. This invention relates to a vehicle-mounted refrigerator device that protects the motor of the vehicle-mounted refrigerator in extremely low-temperature atmospheric conditions by using the detected temperature from a discharge refrigerant temperature detector necessary to generate a drive power source of a predetermined frequency. .

(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,
An example of a vibratory compressor drive control used in the refrigerator is shown in FIG. The vibrating compressor 5 shown in FIG. 4 connects the DC power 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 states. 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 are alternately switched into a conductive state and a non-conductive state in the manner shown in the current waveform shown in FIG. The switching frequency is controlled. To explain in detail, in order to switch the collector current "I _C " in Fig. 5,
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 the figure as a current waveform obtained by multiplying the current amplification factor "h _FE ", I≧h _FE ×I _B is obtained at points P ₁ to P ₃ in the figure, respectively. By providing conditions, the switching transistors TR ₁ and TR ₂ are alternately switched between a conductive state and a non-conductive state, thereby obtaining 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, motor protection protects the on-vehicle refrigerator that drives the compressor 5 using a drive power source that matches the resonant frequency of the vibrating compressor 5 from being undesirably operated in an extremely low temperature atmosphere. As a device, a temperature detection element is provided in the condenser, and the temperature detected by the temperature detection element, that is, the temperature around the condenser is detected. That is, when an on-vehicle refrigerator is operated at extremely low temperatures, the piston of the motor that drives the compressor 5 becomes overstroked.
Since this would destroy the valve, the power supply to the motor was stopped to protect the motor.

(Problems to be solved by the invention) Conventionally, when detecting the condenser temperature (discharge refrigerant temperature) and controlling the output of the drive power supply, a dedicated temperature detection element was required, and wiring for that purpose was required. .

The present invention focuses on the point that a temperature sensing element is provided in the condenser because the drive power source for driving the vibratory compressor adopts a temperature feedback system.
It is an object of the present invention to provide a vehicle-mounted refrigerator device that protects the motor of the vehicle-mounted refrigerator in a low-temperature atmospheric state using the detected temperature detected by the temperature detection element.

(Means for Solving the Problems) Therefore, the in-vehicle refrigerator device of the present invention is an in-vehicle refrigerator device that drives and controls a vibrating compressor using a predetermined frequency corresponding to the load. and a discharge refrigerant temperature detector that detects a temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor. and a drive power generation section that generates a drive voltage of a predetermined frequency based on temperature signals detected by the suction refrigerant temperature detector and the discharge refrigerant temperature detector, respectively, the drive power source The generating section includes: a drive circuit that generates a control signal for generating the drive voltage based on the respective detected temperature signals; a switching element that is turned on and off by the control signal from the drive circuit; and the suction element. a temperature comparator that stops the control signal generation operation in the drive circuit based on a comparison result between the temperature signal from the refrigerant temperature detector and a set temperature signal of the refrigerator; The present invention is characterized by comprising a control signal suppressing means for suppressing the control signal in the drive circuit under a low temperature atmosphere condition in which the temperature signal drops below a predetermined temperature.

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

FIG. 1 is a configuration diagram of an embodiment of a vehicle refrigerator device according to the present invention, FIG. 2 is a schematic configuration diagram of a vehicle refrigerator to which the present invention is applied, and FIG. 3 is a diagram of a vehicle refrigerator to which the present invention is applied. The circuit configuration of one embodiment is shown.

Before explaining the in-vehicle refrigerator device according to the present invention, the outline of the in-vehicle 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. A temperature detector T _s 2 to detect and a temperature detector to detect the temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor 5.
Based on the respective signals from T _d 3, the compressor 5
This is for supplying a drive signal of such a frequency that the motor is driven in a resonant state. Note that the temperature detection section 1
It may be considered that the temperature detected at -1 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 detection sections (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" which are converted into electric 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 transistors TR ₁ and TR ₂ in the figure, and connects the DC power supply V _cc to 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 and 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 signal of the refrigerator set by the volume 24 with the signal from the temperature detector 2 that 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 having 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 used to detect when the in-vehicle refrigerator is connected to a commercial power source, and to drop the voltage of the commercial power source. descend and supply.

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, symbols 1-1, 1-2, 1-
3, 3 to 5, TR ₁ , TR ₂ correspond to those in FIG. 2, and 19 corresponds to those in FIG. 3. Reference numeral 31 represents a drive power generation section, and 32 represents a temperature-voltage conversion section.

Temperature detector 3 detects the temperature relative to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor 5
For example, a thermistor is used, and the temperature detector 3 is attached to the condenser 6. The temperature detector 3 has already been described in FIG. In the case of the present invention, a dual-purpose configuration is adopted. Therefore, the detected temperature detected by the temperature detector 3 is converted into an electrical signal by the temperature-voltage converter 32 in the temperature detector 1-1 provided corresponding to the temperature detector 3. , OR circuit 19
It is input as an output voltage control signal to the drive circuit 1-3 via. Further, the drive circuit 1-3 is stopped under extremely low temperature conditions.

A frequency control signal from the calculation section 1-2 is input to the drive circuit 1-3. The frequency control signal includes a "temperature corresponding to the suction pressure" detected by the temperature detector 2 (not shown in FIG. 1) and a "temperature corresponding to the discharge pressure" detected by the temperature detector 3. The voltage corresponds to the frequency at which the compressor 5 is driven in a resonant state with respect to the resonant frequency of the mechanical system based on the resonant frequency of the mechanical system. The frequency of the output Q of the drive circuit 1-3 that drives the switching transistors TR ₁ and TR ₂ is determined by this frequency control signal, but the frequency of the output Q, which is input to the drive circuit 1-3 described above, is determined by this frequency control signal. The inside of the drive circuit 1-3 is configured to control the outputs of the switching transistors TR ₁ and TR ₂ by a voltage control signal, for example, to reduce the output as the temperature becomes lower. In addition, the car refrigerator has an extremely low atmosphere.
That is, when an attempt is made to operate under an extremely low outside temperature, the drive circuit 1-3 is stopped due to the extremely low temperature detected by the temperature sensor 3, the output Q is completely stopped, and the switching is stopped. Transistors TR ₁ and TR ₂ do not operate. As a result, the motor that drives the compressor 5 does not move, and damage to the valve due to motor overstroke that occurs at extremely low temperatures is avoided.

〔Effect of the invention〕

As explained above, according to the present invention, since the configuration is such that it also serves as a temperature detector necessary for generating a driving power source of a predetermined frequency to the compressor, special temperature detection is performed to protect the motor that drives the compressor. No element is required, and its wiring is also unnecessary.

Furthermore, since the evaporator temperature is also detected, the motor can be easily protected using the signal.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a vehicle refrigerator device according to the present invention, FIG. 2 is a schematic configuration diagram of a vehicle refrigerator to which the present invention is applied, and FIG. 3 is a diagram of a vehicle refrigerator to which the present invention is applied. One example circuit configuration, FIG. 4 is an explanatory diagram explaining conventional compressor drive control, and FIG.
The figure shows an operation explanatory diagram for explaining the operation of the compressor drive control system shown in FIG. 4. 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 , 31 represents a drive power generation section, and 32 represents a temperature-voltage conversion section.

Claims (1)

[Claims] 1. In an on-vehicle refrigerator device that drives and controls a vibrating compressor using a predetermined frequency corresponding to the load, the temperature corresponds to the saturated vapor pressure of the refrigerant sucked by the compressor. a suction refrigerant temperature detector that detects the temperature of the refrigerant compressed by the compressor and a discharge refrigerant temperature detector that detects a temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor; a drive power generation section that generates a drive voltage of a predetermined frequency based on the temperature signals detected by the temperature detectors, and the drive power generation section generates a drive voltage based on the temperature signals detected respectively by the temperature detectors. a drive circuit that generates a control signal for generating the drive voltage; a switching element that is turned on and off by the control signal from the drive circuit; and a temperature signal from the suction refrigerant temperature detector and a set temperature of the refrigerator. a temperature comparator that stops the control signal generation operation in the drive circuit according to a comparison result with the signal, and a temperature comparator that causes the temperature signal from the discharge refrigerant temperature detector to drop below a predetermined temperature A vehicle-mounted refrigerator device comprising a control signal suppressing means for suppressing the control signal in the drive circuit under temperature and atmospheric conditions.