JPH0523347B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a phase control device for an on-vehicle refrigerator, in particular a vibrating compressor that is driven using a drive power source that matches the resonant frequency of the compressor. The present invention relates to a phase control device for an on-vehicle refrigerator that controls the drive power supply voltage of a drive power generation unit according to the applied DC input voltage.

[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 is vaporized. 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, 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 driver 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 figures as a current waveform obtained by multiplying the current amplification factor "h _FE ", I _C ≧h _FE × I _B at positions such as points P ₁ to P ₃ in the figure, respectively. By applying these 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, the drive power generation unit that supplies the drive power that matches the resonant frequency of the vibrating compressor 5 uses a battery installed in the vehicle as the DC input voltage to the drive power generation unit. The input voltage fluctuated, and the voltage of the drive power supply to the compressor 5 fluctuated.

(Problems to be Solved by the Invention) In particular, when the DC input voltage to the drive power generation section is high, the voltage of the drive power supplied to the compressor increases, causing overstroke of the motor that drives the compressor. There was a risk of damage to the motor valve.

The present invention aims to solve the above-mentioned problems, and even if the DC voltage input to the drive power generation section becomes high, the control signal that drives the switching transistor provided in the drive power generation section is provided. An object of the present invention is to provide a phase control device for a vehicle-mounted refrigerator that suppresses a voltage rise of a drive power source by controlling the pulse width of the DC input voltage according to a DC input voltage.

(Means for Solving the Problems) Therefore, the phase control device for an on-vehicle 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 suction refrigerant temperature detector detects a temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor, and a temperature corresponding to the saturated vapor pressure of the refrigerant compressed and discharged by the compressor. A discharge refrigerant temperature detector; and a drive power generation section that generates a drive power source 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 generation section is equipped with a switching control circuit that generates an output Q by inputting a triangular wave voltage and a phase control voltage, and uses the drive power generated by the drive power generation section to perform the above compression. A compressor drive control device for driving a compressor, which includes a level conversion circuit that changes a reference voltage in response to a DC input voltage applied to a drive power generation section, and a level conversion circuit that changes in response to the DC input voltage. A comparator is provided to compare the reference voltage of the circuit with the triangular wave voltage applied to the switching control circuit, and the output Q of the switching control circuit is controlled by using the output of the comparator, which varies in accordance with the DC input voltage, as a gate. It is characterized in that a gate circuit is provided for each passage, and the drive power supply voltage of the drive power generation section is controlled in accordance with the DC input voltage.

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

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is an operational 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. 4 is a diagram in which the present invention is used. 1 shows an example circuit configuration of an on-vehicle refrigerator.

Before explaining the phase control 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 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 (T _s )
The compressor 5 is driven in a resonant state based on the respective signals from 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. 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.

A vibrating compressor 5 supplied with drive power generated by a drive signal supplied from the control circuit 1 compresses the refrigerant and supplies a mixture of gas and liquid to a 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" which are 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 TR ₁ and TR ₂ in the figure, and supplies the DC power supply Vcc to the primary of the transformer 4. This is for supplying current to the side windings 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 a vehicle refrigerator in which the present invention is used as shown in FIG.
2, 1-3, 2 to 5, TR ₁ , and TR ₂ are the same as those in FIG. 3, so their explanations 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 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 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 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 OR 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 FIG. 1, symbols 4, 5, TR ₁ and TR ₂ correspond to those in FIG. 3 already explained, and symbol 3
Reference numeral 1 represents a drive power generation section, 32 a switching control circuit, 33 a level conversion circuit, 34 a comparator, 35 and 36 an AND circuit, 37 and 38 resistors, and 39 and 40 capacitors.

The switching control circuit 32 corresponds to the control circuit 1 in FIG. 3, and includes an output Q of the switching control circuit 32, a switching transistor TR ₁ ,
AND circuits 35 and 36 are connected between TR 2 and TR ₂ , respectively. One end of each input of the AND circuits 35 and 36 are both connected to the output of the comparator 34, and a capacitor 40 is connected to the non-inverting input terminal of the comparator 34. The capacitor 4
0 is charged by the output voltage from the switching control circuit 32, the triangular wave voltage shown in FIG. 2 is input to both ends of the capacitor 40, that is, to the non-inverting input terminal of the comparator 34.
The inverting input terminal of the comparator 34 is connected to the connection point B between the resistors 37 and 38 that constitute the level conversion circuit 33.
The voltage appearing on the resistor 3, that is, the DC input voltage E, is
7 and 38 are applied. Therefore, when the DC input voltage E fluctuates, the voltage applied to the inverting input terminal input to the comparator 34 fluctuates.

Now, when the DC input voltage E increases, the voltage at point B of the level conversion circuit 33, that is, the voltage applied to the inverting input terminal of the comparator 34, changes from e ₀ to
Changes to e ₁ (e ₁ > e ₀ ). Since the triangular wave voltage charged in the capacitor 40 is applied to the non-inverting input terminal of the comparator 34, the comparator 3
The period during which T.4 outputs a logic "H" decreases from T ₀ to T ₁ (T ₀ <T ₁ ) as shown in FIG. The output of the comparator 34 is an AND circuit 35, 3.
Since it is the gate signal of 6, AND circuit 3
The outputs of 5 and 36 decrease during the period shown by the diagonal lines in FIG. The switching transistors TR ₁ and TR ₂ are controlled by these reduced signals, and the phase is controlled in such a way that the time during which the transistors TR ₁ and TR ₂ are turned on is reduced. As a result, the stroke of the motor that supplies power to the compressor 5 via the transformer 4 and drives the compressor 5 with DC current does not increase even when the DC input voltage increases, which may damage the valve of the motor. Nothing will happen.

Conversely, when the DC input voltage drops, the phase is controlled in such a way that the time during which the switching transistors TR ₁ and TR ₂ are turned on increases.

〔Effect of the invention〕

As explained above, according to the present invention, the phase of the switching transistor is controlled in accordance with the DC input voltage input to the drive power generation section, so that even if the DC input voltage becomes high, the compressor The voltage rise of the supplied drive power is suppressed, and overstroke of the motor that drives the compressor does not occur.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is an operational 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. 4 is a diagram in which the present invention is used. 5 is an explanatory diagram illustrating a conventional compressor drive control method, and FIG. 6 is an operation explanatory diagram illustrating the operation of the compressor drive control method shown in FIG. 5. It shows. 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 is a drive power generation section, 32 is a switching control circuit, 33 is a level conversion circuit, 34 is a comparator, 35, 36 are AND circuits, 37, 38
is a resistor, 39 and 40 are capacitors, and TR ₁ and TR ₂ are transistors.

Claims (1)

[Claims] 1. In a compressor drive control device that drives and controls a vibrating compressor using a predetermined frequency corresponding to the load, a suction refrigerant that detects a temperature corresponding to the saturated vapor pressure of the refrigerant sucked by the compressor. a temperature detector; 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 the suction refrigerant temperature detector and the discharge refrigerant temperature detector. and a drive power generation section that generates a drive power supply of a predetermined frequency based on the detected temperature signal, respectively, and by inputting a triangular wave voltage and a phase control voltage to the drive power generation section, output Q, The compressor drive control device includes a switching control circuit that generates a direct current applied to the drive power generation section, and drives the compressor using the drive power generated by the drive power generation section. a level conversion circuit that changes a reference voltage in response to the input voltage; a comparator that compares the reference voltage of the level conversion circuit that changes in response to the DC input voltage with the triangular wave voltage applied to the switching control circuit; At the same time, a gate circuit is provided which passes the output Q of the switching control circuit using the output of the comparator, which changes in response to the DC input voltage, as a gate to drive the drive power generation section in response to the DC input voltage. A phase control device for an on-vehicle refrigerator, characterized by controlling a power supply voltage.