JPS62106257A - Compressor protective system of refrigerator for loading on car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a compressor protection system for an on-vehicle refrigerator, particularly a compressor that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load. An on-vehicle refrigerator that protects the motor of the on-vehicle 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 in a drive control device. The present invention relates to a compressor protection system.

[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. Conventional.

As an example of a vibrating compressor drive control system used in the refrigerator, there is a system as shown in FIG. The compressor 5 shown in the second part of the vibration diagram in the fourth cabinet has switching transistors TR, T
By alternately switching RZ to the m conduction state, DC power V is alternately applied to the primary windings of the transformer 4 with different polarities, and a resonance state is established.

That is, the drive is controlled so as to obtain maximum efficiency.

At this time, the switching transistor TR.

TR2 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, the drive circuit 1-3 is changed so that the collector current "Iゎ°" in Figure 5 is switched.
to switching transistors T R+ , T
Base current "IB" is alternately supplied to the base of Rz. That is, the base current “■8” is converted to a current amplification factor “hF”.
By supplying a so-called trapezoidal waveform as shown in the figures (■ to ■) as a current waveform multiplied by "E", the switching transistor TR is ,, TR2 is alternately switched between a conductive state and a non-conductive state to obtain a driving power source of a desired frequency.As previously explained, a driving power source matching the resonant frequency of the vibrating compressor 5 is used. The compressor 5 was being driven.

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 will overstroke and destroy its valve, so to protect the motor, the power supply to the motor must be cut off. It had been stopped.

(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 detection element is provided in the condenser because the drive power source for driving the vibrating compressor adopts the temperature foot hack method.

It is an object of the present invention to provide a compressor protection system for a vehicle-mounted refrigerator, which 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 compressor protection method for an on-vehicle refrigerator of the present invention includes a compressor drive control device that controls the drive of a vibrating compressor using a predetermined frequency corresponding to the load. a suction refrigerant temperature detector that detects a temperature corresponding to the saturated vapor pressure of the refrigerant taken in by the compressor; and a discharge refrigerant temperature that detects a temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor. a detector; and a drive power generation section that generates a drive power source of a predetermined frequency based on the temperature signals detected by the suction refrigerant temperature detector and the discharge refrigerant temperature detector, respectively. A compressor drive control device that drives the compressor using the generated drive power, the drive power generation unit being driven at the predetermined frequency based on the detected temperature from the discharge refrigerant temperature detector. The present invention is characterized in that the output of the provided switching element is controlled, and the motor is protected in a low-temperature atmospheric state of the on-vehicle refrigerator based on the temperature detected by the discharge refrigerant temperature detector.

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

Fig. 1 shows the configuration of an embodiment of a compressor protection system for an on-vehicle refrigerator according to the present invention, Fig. 2 is a schematic configuration diagram of an on-vehicle refrigerator in which the present invention is used, and Fig. 3 shows an example in which the present invention is used. 1 shows a circuit configuration of an embodiment of an on-vehicle refrigerator.

Before explaining the compressor protection system for an on-vehicle refrigerator according to the present invention, the outline of the on-vehicle refrigerator to which the present invention is applied and the circuit configuration in which the present invention is used will be explained.

In FIG. 2, 1 is a control circuit, 1-1 is a temperature detection section,
I-2 is an arithmetic unit, and 1-3 is a drive circuit.

2.3 is a temperature detector, 4 is a transformer, and 5 is a compressor.

6 represents a condenser, 7 represents a pressure reducer, 8 represents a refrigerator, and 8-1 represents an evaporator.

In the figure, the control circuit 1 includes a temperature detection section 1-1. Composed of a calculation unit 1-2 and a drive circuit 1-3, the refrigerant is compressed by the temperature detector (T,) 2, which detects the temperature corresponding to the saturated vapor pressure of the refrigerant taken in by the compressor 5, and is discharged. In order to supply a driving signal with a frequency such that the compressor 5 is driven in a resonant state based on each signal from the temperature detector (Ta) 3 that detects the temperature corresponding to the saturated vapor pressure of the refrigerant. belongs to. Note that the temperature detected by the temperature detection unit 1-1 may 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 emits heat and liquefies it. Then, the liquefied refrigerant is vaporized in an evaporator 8-1 provided in the refrigerator 8 via the pressure reducer 7, and cools the refrigerator 8 by removing the heat of vaporization. The refrigerant that has absorbed the heat of vaporization is compressed again by the compressor 5. By repeating the above closed cycle, the evaporator 8-
The heat taken away from the condenser 6 will be released in the form of heat from the condenser 6. 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 arithmetic unit 1-2 outputs "temperature corresponding to suction pressure" and "
This is for generating a voltage corresponding to the frequency at which the compressor 5- is driven in a resonant state based on the temperature corresponding to the discharge pressure. and.

The drive circuit 1-3 sends a drive signal of a frequency corresponding to the voltage supplied from the calculation unit 1-2 to the transistor T in the figure.
A DC power supply V is supplied to R+ and TR. This is for supplying current from C to the primary winding of the transformer 4 in the form of a 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 a vehicle refrigerator in which the present invention is used as shown in FIG.
or 5. Since TR, TR2 are the same as those shown in FIG. 2, 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, 13 is a surge absorption circuit, 14 is an overcurrent detection circuit, 15.16 is a relay, 1
7.18 is an AND circuit, 19.20 is an OR circuit, 21 is an inverter, 22 and 23 are diodes, 24 is a volume, and 25 is a shunt.

The thermo device 9 is for setting the indoor temperature of the refrigerator, and the volume 2 provided in the thermo device 9 is
The indoor temperature of the refrigerator is changed according to the setting No. 4.

The evaporator temperature comparator 10 uses the signal of the indoor temperature of the refrigerator set by the volume 24 and the evaporator 8-
It electrically compares the signal from the temperature detector 2 which is detecting the temperature of the evaporator 8-1, and when the set temperature on the thermo device 9 side becomes higher than the temperature on the evaporator 8-1 side, a logic rLJ is output. The output of the logic rLJ becomes a stop signal for the drive circuit 1-3 via an OR circuit 20 having a negative input terminal, and also becomes a stop signal for the drive circuit 1-3 via an AND circuit 17.
The contact of the transformer 4 is turned off through the relay 16.
．． That is, the supply of DC power to the transistors TRI and TR2 is cut off.

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 when commercial power is input.

Outputs logic rHJ. The logic rHJ becomes a stop signal to the drive circuits 1-3 via the OR circuit 20, turns off the contact of the relay 16 via the AND circuit 17, and connects the transformer 4. That is, transistor TR,.

Cut off the DC power supply to TR2. 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 the logic rHJ when the voltage of the input DC power supply is higher than a predetermined voltage. Output. The logic "I(") is connected to the drive circuit 1-3 via the OR circuit 19 to the transistor TR.

The output of TR2 is controlled, and the stroke of compressor 5 is controlled.

The overcurrent detection circuit 14 detects an overcurrent flowing through the transistors TR, TR, together with the shunt 25. When the overcurrent detection circuit 14 detects an overcurrent, it sends the transistors TR, TR, to the drive circuit 1-3. Transistor TR, by outputting an output off latch signal that stops the operation of TR2.

Prevent damage to TR2 etc.

Next, the present invention will be explained in more detail using FIG.

In FIG. 1, reference numeral 1-1. l-2, 1-3°3 to 5. TR,,TR,corresponds to that in Fig. 2,
20 corresponds to that in FIG.

Reference numeral 31 represents a drive power generation section, and 32 represents a temperature-voltage conversion section.

The temperature detector 3 detects the temperature of the refrigerant compressed and discharged by the compressor 5 relative to the air pressure.

For example, a thermistor is used, the temperature detector 3 being attached to the condenser 6. The temperature detector 3 has already been described in FIG. 2, and the temperature-voltage converter 32 that converts the temperature detector 3 and the signal detected by the temperature detector 3, that is, the temperature, into an electrical signal is provided in the present invention. In the case of,
It has a dual-purpose configuration. Therefore, the detected temperature detected by the temperature detector 3 is determined by the temperature-voltage converter 3 in the temperature detector 1-1 provided corresponding to the temperature detector 3.
2, it is converted into an electrical signal and inputted to the drive circuit 1-3 as an output voltage control signal via the OR circuit 20. 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 is based on the "temperature corresponding to the suction pressure" detected by the temperature detector 2 (not shown in FIG. 1) and the "temperature corresponding to the discharge pressure" detected by the temperature detector 3. Based on this, 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.

The frequency of the output Q, Q of the drive circuit 1-3 that drives the switching transistors TR, TR2 is determined by this frequency control signal, but the output voltage control input to the drive circuit 1-3 described above is determined by this frequency control signal. Transistor T for switching by signal
The inside of the drive circuit 1-3 is configured to control the output of R+ and T Rz, for example, to reduce the output as the temperature becomes lower. Furthermore, when the in-vehicle refrigerator attempts to operate in an extremely low atmosphere, that is, in an extremely low outside temperature, the drive circuit 1-3 is stopped due to the extremely low temperature detected by the temperature detector 3.
Outputs Q and Q are completely stopped, and switching transistors T R+ and T Rz 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.

[Effects 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 to generate a drive power source of a predetermined frequency to the compressor, it is possible to protect the motor that drives the compressor. Therefore, no special temperature sensing 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 drawings]

Fig. 1 shows the configuration of an embodiment of a compressor protection system for an on-vehicle refrigerator according to the present invention, Fig. 2 is a schematic configuration diagram of an on-vehicle refrigerator in which the present invention is used, and Fig. 3 shows an example in which the present invention is used. An example circuit configuration of an on-vehicle refrigerator, FIG. 4 is an explanatory diagram explaining a conventional compressor drive control method, and FIG. 5 is an operation explanatory diagram explaining the operation of the compressor drive control method shown in FIG. 4. It shows. In the figure, ■ 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
5 is a transformer, 5 is a compressor, 6 is a condenser, 7 is a pressure reducer, 8 is a refrigerator, 8-1 is an evaporator, 31 is a drive power generation section, and 32 is a temperature-voltage conversion section.

Claims (1)

[Claims] In a compressor drive control device that drives and controls a vibrating compressor using a predetermined frequency corresponding to a load, a suction refrigerant temperature detector detects a temperature corresponding to a saturated vapor pressure of refrigerant sucked by the compressor. 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 temperature signals detected by the suction refrigerant temperature detector and the discharge refrigerant temperature detector, respectively. a drive power generation section that generates a drive power source of a predetermined frequency based on the drive power generation section, and drives the compressor using the drive power generated by the drive power generation section, the compressor drive control device comprising: Based on the temperature detected from the discharge refrigerant temperature detector, the output of a switching element provided in the drive power generation section driven at the predetermined frequency is controlled, and the temperature detected from the discharge refrigerant temperature detector is controlled. A compressor protection system for an on-vehicle refrigerator is characterized in that the motor of the on-vehicle refrigerator is protected in a low-temperature atmospheric condition based on the above.