JPH0765570B2 - Malfunction prevention circuit device for drive power source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a malfunction prevention circuit device for a drive power supply generation unit, and more particularly to a high-speed operation switching control circuit IC used for the drive power supply generation unit of an in-vehicle refrigerator. The present invention relates to a malfunction prevention circuit device for a drive power source generation unit that is configured to operate reliably at a low frequency such as a commercial frequency.

(Prior Art) There is a refrigerator in which a gaseous refrigerant is compressed and liquefied by using an oscillating compressor, and cooling is performed by using heat of vaporization when the liquefied refrigerant is vaporized. Conventionally, as a vibration type compressor drive control system used in the refrigerator, there is one shown in FIG. 5, for example. In FIG. 5, the oscillating compressor 5 switches the switching transistors TR ₁ and TR ₂ to the conductive state alternately to direct the DC power supply V to the windings on the primary side with different polarities of the transformer 4. The voltage is applied alternately and the drive is controlled so that the resonance state, that is, the maximum efficiency is obtained. At this time, the switching transistors TR ₁ and TR ₂ are alternately switched between the conducting state and the non-conducting state in the manner shown by the current waveform in FIG. 6, for example, so that they match the resonance frequency of the vibration type compressor 5. The switching frequency is controlled. More specifically, to switch the Figure 6 diagram in collector current "I _c", the base current "I _B" is alternately supplied from the drive circuit 1-3 to the base of the transistor TR _1, TR ₂ for switching It That is, the base current "I _B" current amplification factor "h _FE"
By supplying a so-called trapezoidal waveform as shown in the figure or shown as the doubled current waveform, by applying the condition of I _c ≧ h _FE × I _{B at} positions such as points P ₁ to P _{3 in} the figure, the switching The transistors TR ₁ and TR ₂ are alternately switched between a conductive state and a non-conductive state to obtain a driving power supply with a desired frequency.
Conventionally, as described above, the compressor 5 is driven by using the drive power source that matches the resonance frequency of the vibration type compressor 5.

As described above, the current of the vibration type compressor 5 is I _c ≧ h _FE
× transistor TR ₁ for switching the conditions of the I _B,
A switching control circuit for high-speed operation is used in the drive power supply generation unit that alternately switches TR ₂ to the conducting state / non-conducting state and controls the switching frequency so as to match the resonance frequency of the vibration type compressor 5. It constituted a low frequency, eg commercial frequency, power supply.

FIG. 7 is a circuit configuration of a conventional drive power supply generation unit, which is a component circuit configuration of a switching control circuit IC for high speed operation, and FIG. 8 is a waveform explanatory diagram for explaining FIG. 7th
In the figure, reference numeral 31 is a switching control circuit IC, 32 is an oscillator, 33 is a comparator, which operates at high speed,
External components attached to the outside of the switching control circuit IC31 to a capacitor, 35 terminals, TR _1, TR ₂ is the switching control circuit a transistor for switching
It is driven by the output Q of the IC.

By charging the capacitor 34 with the rectangular wave voltage output from the oscillator 32, a triangular wave voltage appears as shown in FIG. 8, and the output oscillation frequency of the switching control circuit IC31 is determined. The phase control voltage E for controlling the duty of the output waveform is applied to the inverting input terminal of the comparator 33 operating at high speed via the terminal 35, and the triangular wave voltage of the capacitor 34 and the phase control voltage applied to the terminal 35 are applied. An output off signal is generated by E and the output off signal and the oscillator 32.
The inverted output of Q was created from the output of. In this case, since the gradient of the triangular wave voltage of the capacitor 34 is steep enough to cause the switching control circuit IC31 to switch at high speed, there is no problem in its operation, and the switching control circuit IC31 is designed as such.

(Problems to be solved by the invention) However, if an attempt is made to operate at a low frequency such as a commercial frequency, the gradient of the triangular wave voltage charged in the capacitor 34 becomes gentle, so that the phase control applied to the terminal 35 is controlled. When noise is added to the voltage E, an undesired shift occurs at the time of switching at the rising portion of the output waveform, that is, T ₁ , T ₃ , T _5, etc., which shifts from the resonance frequency in the vibration type compressor described above. There was a drawback that caused.

The present invention is intended to solve the above-mentioned drawbacks and uses a temperature corresponding to the saturated vapor pressure of the refrigerant on the inlet side of the vibration type compressor and a temperature corresponding to the saturated vapor pressure of the refrigerant on the outlet side. Therefore, after adopting a drive power supply that causes a switching operation to resonate with the mechanical vibration of the compressor, a comparator operating at a low speed is used in front of the switching control circuit IC for high-speed operation. The output is replaced with the phase control voltage for the switching control circuit IC for high-speed operation, and it is an object of the present invention to provide a malfunction prevention circuit device for the drive power source generation unit that does not malfunction even at low frequencies such as commercial frequencies. .

(Means for Solving Problems) Therefore, the malfunction prevention circuit device of the drive power source generating unit according to the present invention uses the steam vibration type by using the desired frequency corresponding to the operation of the vibration type compressor in the refrigerator. In a compressor drive control device for driving and controlling a compressor, a temperature corresponding to a saturated vapor pressure of a refrigerant sucked by the compressor in an evaporator used in the refrigerator and the compression in a condenser used in the refrigerator. And a temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the machine, and a drive power source generating unit for generating a drive voltage of the desired frequency, and the drive power source generating unit includes A switching control for high-speed operation in which a triangular wave voltage and a phase control voltage are input and the output pulse width of which changes according to the input level of the phase control voltage. A compressor drive control device comprising a circuit for driving the compressor by using a drive power source generated by the drive power source generating section, wherein the triangular wave voltage applied to the high speed operation switching control circuit and the A low-speed operation comparator for inputting the phase control voltage is provided, and the rectangular wave output of the comparator is replaced with the phase control voltage of the high-speed operation switching control circuit, and switching reliably operates at low frequencies. It is characterized by doing so.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an operation waveform diagram of the present invention, FIG. 3 is a schematic configuration diagram of an on-vehicle refrigerator in which the present invention is used, and FIG. 1 shows a circuit configuration of an example of a vehicle-mounted refrigerator that is installed.

Before describing a malfunction prevention circuit device for a drive power source generating unit according to the present invention, an outline of an in-vehicle refrigerator in which the present invention is used and a 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 detector, 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, 8-1
Represents an evaporator.

In the figure, the control circuit 1 is composed of a temperature detection unit 1-1, a calculation unit 1-2 and a drive circuit 1-3, and detects the temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor 5. The compressor 5 based on the respective signals from the temperature detector (T _s ) 2 and the temperature detector (T _d ) 3 which detects the temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor 5. Is for supplying a drive signal having a frequency such that is driven in a resonance state. It can be considered that the temperature detected by the temperature detection unit 1-1 is substantially the temperature corresponding to the pressure of the refrigerant on the suction side and the pressure of the refrigerant on the discharge side.

The oscillating compressor 5, which is supplied with the driving power generated by the driving signal supplied from the control circuit 1, compresses the refrigerant to supply a mixture of gas and liquid to the condenser 6. It radiates heat to liquefy. Then, the liquefied refrigerant is vaporized by the evaporator 8-1 provided in the refrigerator 8 via the pressure reducer 7 to remove heat of vaporization and cool the refrigerator 8. The refrigerant that has deprived the heat of vaporization is compressed again by the compressor 5. By repeating the closed cycle as described above, the evaporator 8-
The heat taken from 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 detector 1-1 is for converting the signals detected by the temperature detectors (for example, thermistors) 2 and 3 into predetermined electric signals.

In the figure, the calculation unit 1-2 determines that the compressor 5 is in the resonance state based on the "temperature corresponding to the suction pressure" and the "temperature corresponding to the discharge pressure" converted into the electric signal form by the temperature detection unit 1-1. It is for generating a voltage corresponding to a driving frequency. Then, the drive circuit 1-3 is the arithmetic unit 1-
A drive signal having a frequency corresponding to the voltage supplied from ₂ is supplied to the transistors TR ₁ and TR ₂ in the figure so that the primary side winding of the transformer 4 is in the form of a rectangular wave from the illustrated DC power supply V _cc. The current is supplied to the windings having different polarities in an alternating manner. 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 state of resonance, that is, driven with maximum efficiency.

In the configuration of one embodiment of the on-vehicle refrigerator in which the present invention shown in FIG. 4 is used, reference numerals 1-1, 1-2, _1-3 , 2 to 5, TR ₁ , T
Since R ₂ is the same as that in FIG. 3, its explanation is omitted.

Reference numeral 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 and 16 are relays, 17 and 18 are AND circuits, 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 24 provided in the thermo device 9 is used.
The room temperature of the refrigerator can be changed according to the setting.

The evaporator temperature comparator 10 electrically compares the signal of the indoor temperature 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 the thermostat 9 The set temperature on the side is the evaporator 8
When the temperature becomes higher than the -1 side temperature, a logic "L" is output. The output of the logic "L" is an OR circuit having a negative input terminal.
It becomes a stop signal to the drive circuit 1-3 via 20 and turns off the contact of the relay 16 via the AND circuit 17, and the direct current to the transformer 4, that is, the transistors TR ₁ and TR ₂ via the relay 16. Turn off the power supply.

The transformer 11 is for lowering the voltage of the commercial power source for detection when the vehicle-mounted refrigerator is connected to the commercial power source. The voltage of the commercial power source is supplied to the AC detector 12 connected to the secondary side. To descend and supply.

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

The surge absorbing circuit 13 absorbs the surge voltage of the input DC power supply and supplies the DC power to the drive circuit 1-3, and when the voltage of the input DC power supply is higher than a predetermined voltage, the logic “H Is output. The logic “H” is a transistor for the drive circuit 1-3 through the OR circuit 19.
The strokes of the compressor 5 are controlled by controlling the outputs of TR ₁ and TR ₂ .

The overcurrent detection circuit 14 includes a shunt 25 and a transistor TR.
_1, which detects an overcurrent flowing through the TR _2, overcurrent when the detection circuit 14 detects the overcurrent, outputs the off-latch signal to the drive circuit 1-3 is stopped transistors TR _1, TR ₂ and operation Is output to prevent damage to the transistors TR ₁ , TR _2, etc.

Next, the present invention will be described in detail with reference to FIGS.

In FIG. 1, reference numerals 31 to 35, TR ₁ and TR ₂ correspond to those already described in FIG. 7, and reference numeral 36 represents a comparator for low speed operation. The inverting input terminal of the comparator 36 operating at a low speed is connected to the capacitor 34 that exhibits a triangular wave voltage, and the phase control voltage E is applied to the non-inverting input terminal of the comparator 36. The output of the comparator 36 is connected to the terminal 35.

It goes without saying that the switching control circuit IC31, the capacitor 34 and the comparator 36 are a part of the drive circuit 1-3 shown in FIG.

The rectangular wave voltage oscillated from the oscillator 32 at the commercial frequency is
As the capacitor 34 is charged, a triangular wave voltage of commercial frequency appears on the capacitor 34. That is, the triangular wave voltage of the commercial frequency is also applied to the inverting input terminal of the comparator 36. On the other hand, the non-inverting input terminal of the comparator 36 is applied with the phase control voltage E which determines the duty of the output waveform. Therefore, the output of the comparator 36 changes from “H” to “L” at time T ₁ when the triangular wave voltage input to the inverting input terminal of the comparator 36 becomes higher than the phase control voltage E applied to the non-inverting input terminal. Invert. Then, at time T ₂ when the charging voltage of the capacitor 34 becomes zero, the output of the comparator 36 is inverted again from “L” to “H”, and at time T ₃ when the triangular wave voltage of the next cycle becomes higher than the phase control voltage E. The output of the comparator 36 is inverted from "H" to "L".
In this way, between T ₀ −T ₁ , T ₂ −T ₃ , T ₄ −T ₅ where the triangular wave voltage charged in the capacitor 34 is lower than the phase control voltage E,
The output of the comparator 36 is "L", and in between the triangular wave voltage charged in the capacitor 34 in the reverse of the phase control voltage higher T ₁ -T ₂ than _{E, T 3 -T 4, T} 5 -T 6 The output of the comparator becomes "H". That is, at times T ₁ , T ₃ and T ₅ , there is a rapid change from “H” to “L”.

On the other hand, in the comparator 33, the output voltage of the comparator 36 is compared with the triangular voltage charged in the capacitor 34, and the voltage input to the inverting input terminal of the comparator 33 at the times T ₁ , T ₃ , T ₅ is “ Since there is a sudden change from "H" to "L", the output of the comparator 33 becomes as shown in FIG. 2, and it is difficult for a malfunction to occur at its rising.

Further, since the comparator 36 is of a low speed type, even if noise is added to the phase control voltage E input to the non-inverting input terminal of the comparator 36, its influence is unlikely to appear in the output of the comparator 36. Yes.

(Effects of the Invention) As described above, according to the present invention, the switching control circuit IC for high-speed operation used in the drive power source generation unit of the in-vehicle refrigerator can reliably operate at a low commercial frequency. It does not deviate from the resonance frequency of the vibration type compressor. Therefore, the operation of the refrigerator is stable.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an operation waveform diagram of the present invention, FIG. 3 is a schematic configuration diagram of an on-vehicle refrigerator in which the present invention is used, and FIG. FIG. 5 is an explanatory view for explaining the conventional compressor drive control system, and FIG. 6 is an operation explanatory view for explaining the operation of the compressor drive control system shown in FIG. , FIG. 7 shows the circuit configuration of a conventional drive power source generator, and FIG. 8 shows the operation waveform diagram of FIG. In the figure, 1 is a control circuit, 1-1 is a temperature detection unit, 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, 8-1 is an evaporator, 31 is a switching control circuit IC , 32 is an oscillator, 33 is a comparator, 34 is a capacitor, and 36 is a comparator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoya Kawakami 3 Hayakawa, Nitta-machi, Nitta-gun, Gunma Prefecture Hayakawa, No. 3 Nitta Factory, Sawafuji Electric Co., Ltd. (72) Yoshiaki Fujisawa Nitta-machi, Nitta-gun, Gunma Prefecture Hayakawa No. 3 Hayakawa No. 3 Sawafuji Electric Co., Ltd. Nitta factory (72) Inventor Noriyoshi Yamada No. 3 Nitta-cho, Nitta-gun Gunma Hayakawa No. 3 Hayakawa No. 3 Sawafuji Electric Co., Ltd. Nitta factory

Claims (1)

[Claims] 1. An evaporator used in the refrigerator in a compressor drive control device for driving and controlling the vibration type compressor using a desired frequency corresponding to the operation of the vibration type compressor in the refrigerator. Signal of both the temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor and the temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor in the condenser used in the refrigerator Based on the above, a drive power source generating unit for generating a drive voltage of the desired frequency is provided, and the triangular wave voltage and the phase control voltage are input to the drive power source generating unit and the input level of the phase control voltage is set. A switching control circuit for high-speed operation whose output pulse width changes according to the driving power supply generated by the driving power supply generation unit is used to drive the compressor. And a low speed operation comparator for inputting the triangular wave voltage applied to the high speed operation switching control circuit and the phase control voltage, and a rectangular wave output of the comparator. A malfunction prevention circuit device for the drive power supply generation unit, characterized in that the switching control circuit for high-speed operation is replaced with the phase control voltage so that switching can operate reliably at low frequencies.