JPH0880090A - Power unit of oscillatory compressor - Google Patents

Abstract

PURPOSE: To surely detect each maximum peak and obtain AC voltage of frequency following the ripple of mechanical resonant frequency by detecting each maximum peak which appears in the first half and the second half of the waveform of a load current, making the detection time of the first half longer than the detection time of the latter half. CONSTITUTION: A cycle dividing circuit 15 divides one cycle of frequency oscillated by a variable oscillator 14 at a specified rate where the time of the first half is longer than that of the second half, and the waveform of a load current is separated into the first half and the second half through switches 19 and 20, and they are inputted into each peak detecting circuits 17 and 18. An error amplifying circuit 16 sends a control signal, which zeros the difference between these two peak values, to the variable oscillator 14 through the time constant circuit consisting of a capacitor 24 and a resistor 25, and makes the oscillated frequency follow the ripple of the resonant frequency of an oscillatory compressor 1 so as to improve the mechanical efficiency. Furthermore, a voltage detecting circuit 38 and an atmosphere detecting circuit 39 are provided, and the output width of the oscillated frequency of the variable oscillator 14 is controlled to prevent the occurrence of valve beat of the oscillatory compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a vibration type compressor, and more particularly, to a power supply device for a vibration type compressor, which is provided with a switching element and alternately switches to supply power to the vibration type compressor. A vibration that generates an AC voltage that follows the resonance frequency of the vibration type compressor in response to mechanical fluctuations of the resonance frequency to make the vibration type compressor efficient and endure long-term use of the vibration type compressor. The present invention relates to a power supply device of a mold compressor.

[0002]

2. Description of the Related Art Since the mechanical resonance frequency of a vibration type compressor is determined in advance due to its structure, in a power supply device of a conventional vibration type compressor which uses a DC power source, for example, a battery as a driving source, the battery voltage is Based on this, an AC voltage having a fixed frequency was generated, and the AC voltage having this frequency was supplied to the vibration type compressor.

Further, no particular attention has been paid to the mechanical movement of the vibration type compressor with respect to the power supply voltage and the ambient temperature.

[0004]

However, in the vibration type compressor, the resonance frequency of the vibration type compressor changes depending on the load fluctuation and the usage environment. If it was kept constant, there was a drawback that the efficiency was poor.

Further, when the power supply voltage is increased, valve vibration occurs in the vibration type compressor, and there is a defect that valve vibration occurs even when the ambient temperature is low. Particularly when a battery is used as a driving source, an efficient driving method is desired.

Therefore, the applicant of the present application detects the current waveform flowing in the vibration type compressor with a detection resistor and divides the current waveform in the middle of the first half and the second half in order to catch two peaks appearing in the current waveform. An application for a configuration in which an alternating voltage having a frequency such that the respective average values and integrated values are equal in the first half mountain portion and the second half mountain portion is generated and supplied to the vibration type compressor was filed first (special feature Wishhei 5-252772
issue).

The present invention has been made in view of the above points, and is a further improvement of the above filed application. The present invention includes a switching element for converting direct current into alternating current, In the power supply device of the vibration type compressor configured to supply power to the vibration type compressor by alternately switching, in detecting each maximum peak appearing in the first half and the second half of the current waveform flowing in the vibration type compressor,
Regardless of fluctuations in frequency, the peak detection time in the first half is made longer than the peak detection time in the second half to keep the maximum peak detection time in the first half and the peak detection time in the second half to be constant. Based on, generate an AC voltage with a frequency such that the maximum peak in the first half and the maximum peak in the latter half are equal, and drive with the AC power supply,
It is an object of the present invention to provide a power supply device for a vibration type compressor in which valve striking of the vibration type compressor does not occur with respect to the power supply voltage and the ambient temperature.

[0008] The patent applicant makes the vibration type compressor always drive under optimum conditions by matching the vibration cycle of the electric vibration system in the vibration type compressor with the natural vibration cycle of the mechanical vibration system. Filed (Japanese Patent Application Laid-Open No. 61-
173676).

It has also been found that the efficiency of the vibration type compressor is maximized in the vicinity of the frequency where the difference between the peaks of the first half and the latter half of the current waveform flowing through the vibration type compressor is minimized.

[0010]

In order to solve the above-mentioned object, the power supply device of the vibration type compressor of the present invention comprises a DC power supply,
Vibration type including a polarity inversion circuit that inverts the polarity of a DC power supply, an inverter circuit unit that includes two switching elements and that converts DC to AC by alternate switching, and a control unit that controls the inverter circuit unit In the power supply device of the compressor, a current detecting means for detecting a current flowing through the vibration type compressor is provided, and the control section includes a variable oscillator whose oscillation frequency is variable, and one cycle of the oscillation frequency of the variable oscillator. A period division circuit that divides at a predetermined rate where the time is longer than the latter half time, an electronic switch that captures the current waveform flowing in the current detection means at the division time of the first half and second half that is output by the period division circuit, and that is captured respectively through the switch electron The peak detection circuit for detecting the peak of the generated current waveform and the two peaks detected by the peak detection circuit are compared, A frequency tracking circuit having an error amplification circuit for varying the oscillation frequency of the variable oscillator according to the difference; and a switching element control circuit for alternately switching the switching elements at the oscillation frequency of the variable oscillator, further comprising the DC power supply Voltage detecting circuit for detecting the voltage of the variable oscillator and for varying the output width of the variable oscillator based on the DC voltage, and for detecting the ambient temperature, and for detecting the ambient temperature for varying the output width of the variable oscillator based on the ambient temperature. The vibration type compressor is driven by an AC power source having a frequency that minimizes the current flowing through the vibration type compressor, and the efficiency of the vibration type compressor is improved and the life of the vibration type compressor is extended. It is characterized by doing so.

When the DC power source is a battery, a battery monitor circuit for monitoring the drop of the battery and a thermo control circuit for controlling the internal cold storage temperature are provided to protect the battery and save electric power.

[0012]

The maximum peak of the current waveform flowing through the current detecting means is detected in a divided time period in which the first half time output from the period dividing circuit is longer than the latter half time. In such a case, the maximum peak in the first half can be reliably captured, and an AC voltage having a frequency that follows the mechanical resonance frequency of the vibration type compressor can be generated. Since the vibration type compressor is driven by the AC power source, the efficiency of the vibration type compressor is improved.

Then, the power supply voltage and the ambient temperature are detected,
Since the output width of the variable oscillator is varied based on the power supply voltage and the ambient temperature, valve striking of the vibration type compressor does not occur and the life of the vibration type compressor is extended.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of a power supply device for a vibration type compressor according to the present invention. FIG. 1 shows a power supply device of an alternating-current / direct-current type vibration type compressor, 1 is a vibration type compressor, 2 is a battery, 3 is a polarity reversing circuit, and 4 and 5 are FE.
T transistor, 6 is an inverter circuit section, 7 is a control section,
8 a shunt resistor, 9 a switching element control circuit, 10
Is a frequency tracking circuit, 11 flip-flop circuits, 12,
13 is a driver, 14 is a variable oscillator, 15 is a period division circuit, 16 is an error amplification circuit, 17 and 18 are peak detection circuits, 19 and 20 are electronic switches, 21 is an amplification circuit, 2
2, 23 are capacitors, 24, 25 are resistors, 31 is a commercial AC power supply, 32 is an AC-DC converter, 33 is an automatic switcher, 34 is a relay coil, 35 is a relay contact, 36, 3
Reference numeral 7 denotes a terminal 38, a voltage detection circuit, and 39, an atmosphere detection unit.

The vibration type compressor 1 is a compressor of a refrigerator operating with a low AC voltage, for example, a 12V system or a 24V system. The battery 2 is a direct-current power source such as that mounted on a vehicle, has a voltage of 12V system or 24V system, and serves as a power source of the vibration type compressor 1 while the vehicle is moving. In the following examples, a 12V system will be described.

The polarity reversing circuit 3 is a circuit for reversing the polarity of a DC power supply such as a battery, and is a circuit for obtaining two positive and negative power supplies. The polarity of the battery 2 is -12V when the voltage of the battery 2 is 12V. It is a circuit that generates a voltage.

Explaining in detail with reference to FIG. 2, the operation of the OP amplifier 41 turns on and off the transistor 42,
Generate a pulse. This pulse is a choke coil 43
, The electromagnetic energy is accumulated in the choke coil 43. When the transistor 42 is turned off, the current flowing in the choke coil 43 cannot be changed suddenly and the current continues to flow, and the electromagnetic energy accumulated in the choke coil 43 is transferred to the capacitor 44 and the diode 45 circuit. To charge the capacitor 44
The diode 45 side of is made negative. That is, the diode 45
A DC voltage having a polarity opposite to the voltage of the battery 2 is generated on the anode side of. The on / off ratio of the transistor 42 is determined by the selection of the resistors 46 and 47, the potential of the negative voltage can be arbitrarily changed, and the potential of the negative voltage can be made constant regardless of the load. This will be described in more detail with reference to FIG.

The inverter circuit section 6 is provided with two FET transistors 4 and 5. The FET transistor 4 and the FET transistor 5 are alternately turned on to generate an AC voltage, and the vibration type compressor 1 is concerned. An alternating voltage is supplied.

The control unit 7 includes a switching element control circuit 9 and a frequency tracking circuit 10. The switching element control circuit 9 controls the FET transistor 4 and the FET transistor 5 of the inverter circuit section 6 to be alternately turned on. Output a signal. At this time, the frequency tracking circuit 10 controls the inverter circuit unit 6 to generate an AC voltage having a frequency that tracks the mechanical resonance frequency of the vibration type compressor 1.

As can be seen from FIG. 1, with the vibration type compressor 1 as a load, the FET transistor 4 and the FET transistor 5 are provided.
In the control unit 7, the single end push pull (SEP
P) circuit is configured, and positive and negative AC voltages centered on zero potential are applied to the vibration type compressor 1. Therefore, one end of the vibration type compressor 1 can be dropped to the ground, and the cord itself can be connected to the case itself of the vibration type compressor 1 as shown in FIG. The structure is also simplified.

The shunt resistor 8 detects the current flowing through the vibration type compressor 1, and the vibration type compressor 1 when the FET transistor 5 is driven and a negative AC voltage is applied to the vibration type compressor 1. It is designed to detect the current that flows through.

The switching element control circuit 9 is provided with a flip-flop circuit 11 and drivers 12 and 13, and the frequency oscillated by a variable oscillator 14 described later is divided by 1/2 in the flip-flop circuit 11 to be divided into half cycles. During the half-cycle pulse output period, the
The ET transistors 4 and 5 are controlled to be alternately turned on. The drivers 12 and 13 are, for example, PW
The FET transistors 4 and 5 may be controlled by M control.

The frequency tracking circuit 10 includes a variable oscillator 14,
The cycle division circuit 15, the error amplification circuit 16, the two peak detection circuits 17 and 18, the electronic switches 19 and 20, the amplification circuit 21, the capacitors 22 and 23, and the resistors 24 and 25 are provided.

The oscillating frequency of the variable oscillator 14 varies according to the time constants of the resistors 24 and 25 and the capacitor 22,
The oscillation frequency is input to the flip-flop circuit 11 and the period division circuit 15 of the switching element control circuit 9. Then, the period dividing circuit 15 divides one period of the oscillation frequency of the variable oscillator 14 at a predetermined ratio in which the first half time is longer than the second half time, and the electronic switch 1 is divided in the first half second half.
9 and 20 are closed, and the current waveform flowing through the shunt resistor 8 is captured in synchronization with the ON time of the FET transistor 5. The maximum peak of the current waveform of each current fetched through the electronic switches 19 and 20 is detected by the peak detection circuits 17 and 18, and the two detected peaks are compared by the error amplification circuit 16, The oscillation frequency of the variable oscillator 14 is changed according to the difference.

The AC-DC converter 32 is a commercial AC power supply 31.
Is used when driving the vibration type compressor 1 and converts the AC voltage of the commercial AC power supply 31 into a DC voltage of the same potential as the DC voltage of the battery 2.

When the commercial AC power supply 31 is connected to the terminal 37, the automatic switching unit 33 has priority over the DC power supply on the battery 2 side and connects the DC power supply on the AC-DC converter 32 side. 38 is a voltage detection circuit, 39 is an atmosphere detection unit voltage detection circuit 38, which detects the voltage of the DC power supply, for example, the voltage of the battery 2, and the variable oscillator 1 based on the DC voltage.
The output width of 4 is changed.

The atmosphere detecting section 39 detects the ambient temperature of the refrigerator and varies the output width of the variable oscillator 14 based on the ambient temperature. Although not shown in FIG. 1, a battery monitor circuit for monitoring the drop of the battery 2 and a thermo control circuit for controlling the internal temperature are provided. When the battery voltage drops below a certain level, the battery monitor circuit stops the operation of the controller along with the polarity reversing circuit, and stops the power supply to the battery. At this time, the operation of the control unit is stopped together with the polarity reversing circuit, and the power supply to the battery is stopped to save the power of the battery power supply.

The operation of the power supply device for the vibration type compressor according to the present invention having the above-described structure will be described with reference to the operation waveform explanatory diagram of FIG. The present invention will be described assuming that the power supply device of the vibration type compressor according to the present invention drives a refrigerator installed in, for example, an automobile or a refrigerator in which the container itself is a refrigerator.

While the refrigerator is moving, the DC power source of the battery 2 mounted on the automobile or the like is automatically switched by the automatic switching device 3.
It is supplied to the vibration type compressor 1 via 3. That is, the DC voltage of the battery 2, for example, 12V is input to the polarity reversing circuit 3 via the automatic switch 33, and -12V is generated at the output terminal of the polarity reversing circuit 3 as described above. This ± 12
The voltage of V is applied to the FET transistors 4 and 5 in the inverter circuit unit 6.

The variable oscillator 14 oscillates a pulse having a designed resonance frequency of the vibration type compressor 1, for example, when the resonance frequency is 50 Hz, the lower limit is 45 × 2 Hz and the upper limit is 55 × 2 Hz. Is set to. The setting of the oscillation frequency in this range is determined by the time constant CR of the capacitance C of the capacitor 22 connected to the variable oscillator 14 and the resistance R of the variable oscillator 14 when the resistor 24 is viewed from the side. .

The frequency generated from the variable oscillator 14 is divided by half in the flip-flop circuit 11 and divided into half cycles, and the FET transistor 4 is output by the driver 12 during the pulse output period of the half cycle. 4 [2] is driven by the drive signal, and the FET transistor 5 is driven by the drive signal output from the driver 13 in FIG. 4 [3]. Therefore, the FET transistor 4 and the FET transistor 5 are alternately controlled to be turned on, and the inverter circuit unit 6 generates the AC voltage shown in FIG. 4 [4]. This AC voltage is supplied to the vibration type compressor 1.

In the vibration type compressor 1, the current having the waveform shown in FIG. 4 [5] flows due to the alternating turn-on of the FET transistors 4 and 5. When the FET transistor 5 therein is turned on, the vibration type compression is performed. The current flowing in the machine 1 (Fig. 4 [6]) is detected by the shunt resistor 8 and the shunt resistor 8
The current flowing in the vibration type compressor 1 detected by is amplified by the amplifier circuit 21 as appropriate.

On the other hand, the oscillation frequency oscillated from the variable oscillator 14 is input to the period dividing circuit 15, and the period dividing circuit 15 makes one period of the oscillation frequency of the variable oscillator 14 a predetermined ratio in which the first half time is longer than the second half time. Is divided by. The first half of FIG. 4 [8] output from A of the period division circuit 15
The electronic switch 19 is turned on in the divided time of, and the electronic switch 20 is turned on in the latter divided time of FIG. 4 [7] output from B of the period division circuit 15.

Therefore, of the current flowing through the vibration type compressor 1 that has been appropriately amplified by the amplifier circuit 21, the first half of FIG.

The current waveform of [9] is taken in through the electronic switch 19, and the current waveform is input to the peak detection circuit 17. The current waveform of the latter half of FIG. 4 [10] is taken in through the electronic switch 20, and the current waveform is input to the peak detection circuit 18.

The respective current waveforms input to the peak detecting circuits 17 and 18 are
The maximum peak at 18 was obtained (Fig. 4 [11], [1]
2]), the error amplification circuit 16 compares the two maximum peaks on the other hand, for example, with the maximum peak obtained by the peak detection circuit 17 as a reference, and the deviation is zero. Output a signal. This control signal charges the capacitor 23.

If the charge amount of the capacitor 23 due to the control signal from the error amplifier circuit 16 is small and the voltage at the connection point Y between the capacitor 23 and the resistor 25 becomes low, the variable oscillator 14 will be explained. The constant CR changes. Accordingly, the oscillating frequency generated from the variable oscillator 14 increases accordingly, and a control signal that makes the difference between the maximum peaks of the current waveforms of the two input to the error amplification circuit 16 zero is output and stabilized. . That is, it becomes a form that follows the resonance frequency of the vibration type compressor 1. On the contrary, when the voltage at the connection point Y becomes high, the oscillation frequency generated from the variable oscillator 14 becomes low and becomes equal to the resonance frequency of the vibration type compressor 1.

FIG. 3 is a diagram for explaining the detection of the maximum peak in each waveform. In this way, one cycle of the oscillation frequency of the variable oscillator 14 is divided at a predetermined ratio in which the first half time is longer than the second half time, and the first half thereof is divided. By taking in the electric current flowing in the vibration type compressor 1 with the time longer than the latter half time, even when the peak in the first half appears in the middle or later (see FIG. 3).
D), the two maximum peaks can be reliably captured in each of the first half and the second half, and the resonance frequencies of the vibration type compressor 1 can be matched.

A in the figure shows the case where the driving frequency of the vibration type compressor 1 is the optimum frequency, and the maximum peak in the first half time and the maximum peak in the second half time are almost equal. At this time, the efficiency of the vibration type compressor 1 is close to the maximum as described above, and the current value at that time is the minimum.

B in the figure shows the case where the drive frequency of the vibration type compressor 1 is low, and C in the figure shows the case where the drive frequency of the vibration type compressor 1 is high. In the case of B, as described above, the control signal for increasing the oscillation frequency of the variable oscillator 14 is output from the error amplifying circuit 16 so as to have the waveform as shown in A of FIG. In the case of C, conversely, a control signal for lowering the oscillation frequency of the variable oscillator 14 is output from the error amplification circuit 16 so as to have a waveform as shown in A of FIG.

Reference character E in the same figure shows that the first half time (G in the same figure) is divided longer than the second half time (F in the same figure) by setting the level to L.
Even if the resonance frequency changes due to load fluctuation of the vibration type compressor 1, the oscillation frequency that follows the resonance frequency is generated from the variable oscillator 14, and the FET in the inverter circuit unit 6 is passed through the switching element control circuit 9. Transistor 4 and F
Since the ET transistor 5 and the ET transistor 5 are alternately turned on, the vibration type compressor 1 can be driven in the most efficient state.

The voltage detection circuit 38 detects the power supply voltage when the battery 2 has a high power supply voltage due to overcharge or the like, and reduces the output width of the variable oscillator 14 to reduce the FE.
The ON time width for alternately turning on the T-transistor 4 and the FET transistor 5 is reduced to prevent the valve striking of the vibration type compressor 1 from occurring.

Further, the atmosphere detecting section 39 detects the ambient temperature of the refrigerator, and when the ambient temperature becomes low, the output width of the variable oscillator 14 is similarly reduced and the FET transistor 4 and the FET transistor 5 are alternately arranged. The time width of turning on is turned on to prevent the valve striking of the vibration type compressor 1 from occurring.

When the automobile arrives at a stop or the like and the commercial AC power source 31 is connected to the terminal 37, the AC-DC converter 32
Outputs 12 V, which has the same potential as the DC voltage of the battery 2. The direct current voltage 12V from the AC-DC converter 32 energizes the relay coil 34 and causes the relay contact 35 to be AC.
-Switch to the DC converter 32 side. The driving by the commercial AC power supply 31 also operates in exactly the same manner as in the case of the battery 2 described above, and an AC voltage having a positive / negative centered on zero potential is applied to the vibration type compressor 1.

FIG. 5 shows a circuit diagram of a concrete example of the power supply device for the vibration type compressor according to the present invention, and FIG. 6 shows the frequency tracking circuit, the battery monitor circuit and the thermo control circuit used in FIG. 2 is a circuit diagram of a specific example of the embodiment.

In FIGS. 5 and 6, the polarity inverting circuit 3 described in FIG. 1 is constructed using FET transistors. That is, in addition to the FET1, the choke coil 43, the diode D3, the OP amplifier 202 in the IC2 (for example, TL494), the capacitor C5, and the resistors R8 to 10,1.
It is composed of 4 and 15 and has a diode D as described in FIG.
A negative voltage of -12 V is generated on the anode side of No. 3. Since FET1 is used as a switching element, the FET1
The power source for driving is obtained by a charge pump type circuit including a diode D1, a resistor R1, a constant voltage diode ZD1, and a capacitor C1. In other words, assuming that the source side of FET1 is a temporary ground, + 12V (battery 2
Voltage). When the FET1 is turned off, its source becomes a negative voltage, and at that time, the diode D1 conducts to charge the capacitor C1. When the FET1 turns on, its source rises to + 12V, but the voltage charged in the capacitor C1 is always + 12V with respect to the source.

The gate voltage of FET1 is driven through a high speed photocoupler IC1 (eg TLP550). The drive circuit composed of the transistors TR1 and TR2, the diode D2, the capacitor C2, and the resistors R3 to R7 is a general high-speed circuit, and the drive circuit is controlled by the transistor 2 in the IC2 (for example, TL494).
01.

Inverted output voltage Vout by resistors R14 and R15
Is detected and the detection voltage R15.Vout / (R14 +
FET so that the sum of R15) and the internal reference voltage (Vref) appearing at pin number 14 of IC2 is always 0V.
Controls the pulse width generated by 1.

Vref + R15.Vout / (R14 +
R15) = 0 to Vout =-(1 + R14 / R15)
-It becomes Vref, and by appropriately selecting the resistors R14 and R15, it is possible to create -12V having the same absolute value as the voltage of the battery 2. The oscillation frequency of IC2 is determined by the time constant of the capacitor C3 and the resistor R13, and is set to about 50 KHz.

The two FETs 2 and 3 for supplying the AC voltage to the vibration type compressor 1 constitute a so-called SEPP circuit as described with reference to FIG. Generally F
Since ET needs to apply a voltage of about 12 V to its source as a gate voltage, a power supply voltage of a different system is prepared for each.

That is, the power source of the FET2 is the diode D.
4, the resistance R16, the constant voltage diode ZD2, and the capacitor C7 obtain + 12V with respect to the source of the FET2. The source of the FET2 is FE when the FET2 is off.
Since T3 is turned on and therefore the drain-source voltage of the FET2 is 24V, the constant voltage diode ZD2 is inserted to bring the voltage to + 12V. Further, the photocoupler IC4-2 / 2 (for example, TLP521) and the resistor R19
Together with this, it constitutes a driver of the FET 2, which corresponds to the driver 12 of FIG.

The power source of the FET3 is + 12V with respect to the source of the FET3 by the diode D5 and the capacitor C6. In other words, when the FET3 is on, the current flows from the ground through the diode D5, so that the voltage does not exceed +12 V and the constant voltage diode is not required. FE together with photo coupler IC 4-1 / 2 and resistor R20
It constitutes a driver of T3, which corresponds to the driver 13 of FIG.

The gate drive signals of the FETs 2 and 3 are photocoupler IC4-2 which emits light by alternately turning on / off the transistors 301 and 302 in the IC3 (eg SG3524) corresponding to the variable oscillator 14 and the flip-flop circuit 11 of FIG. Input via / 2, 1/2. Since its operating frequency is as low as 50 to 60 Hz, it is directly driven by one transistor in the general-purpose photocoupler IC4-2 / 2, 1/2.

To prevent the transistors in the photocouplers IC4-2 / 2 and 1/2 from being turned on at the same time, a resistor R2 is provided.
It is set so that a fixed rest period occurs between 2 and 23. The oscillation frequency of the IC3 is determined by the time constants of the resistor R21 and the capacitor C8 connected to the pin numbers 6 and 7, respectively, but in order to perform the frequency tracking described later, the pin number 6 is different from the frequency tracking circuit. Signal is input to change the time constant of the resistor R21 and the capacitor C8 to change the oscillation frequency. That is, the oscillation frequency of the IC3 includes a current mirror circuit in which the current flowing into the capacitor connected to the pin number 7 is equal to the current flowing into the resistor connected to the pin number 6, and the current flowing from the pin number 6 is controlled. By doing so, the oscillation frequency can be changed.
The resistor R21 and the capacitor C8 correspond to the resistor 24 and the capacitor 22 of FIG. 1, respectively.

FIG. 4 appearing on pin number 7 of the IC3.
[1] With the generation of the sawtooth wave shown in the figure, the transistors 301 and 302 described above are alternately turned on and off.
The gate drive signals of the FETs 2 and 3 shown in [2] and [3] are generated in synchronization with the sawtooth wave.

The current flowing in the vibration type compressor 1 is detected by the detection resistor R24 connected to the source side of the FET 3 when a negative AC voltage is supplied. This detection resistor R2
Reference numeral 4 corresponds to the shunt resistor 8 in FIG. The reason why the current on the negative voltage side is detected is that the negative voltage is stabilized by the polarity reversing circuit 3 in the preceding stage, and there is an advantage that it is not easily affected by the ripple voltage.

In FIG. 6, 10 corresponds to that of FIG. 1, 51 is a battery monitor circuit, and 52 is a thermo control circuit. In the figure, the detection resistor R24
The detection current detected by is appropriately amplified by the OP amplifier OP1-1, and the analog switches SW1 and SW
2 are input respectively. The circuit of the OP amplifier OP1-1 and the resistors 27 to 30 corresponds to the amplifier circuit 21 of FIG.

On the other hand, the sawtooth wave shown in FIG. 4 [1] output from the pin No. 7 of the IC3 is the OP amplifier OP2-4.
Is input to the sawtooth wave and is compared with a reference voltage divided by resistors R43 and R44. The OP amplifier OP2-4 has pin numbers 12 and 13 of IC3.
The half cycle in one cycle of ON / OFF output from is divided by a predetermined ratio by setting the resistors R43 and R44, the first half time being longer than the second half time. Analog switch SW
1, SW2, and the analog switches SW1 and SW2 are turned on for the respective times.

Therefore, in the current waveform detected by the detection resistor R24, the ON time of the analog switch SW1 is shown in FIG.

The waveform of [9] is captured and the analog switch SW
2 captures the waveform of FIG. 4 [10]. This O
P amplifier OP2-4, transistor TR5, resistor R41
1 to 46 correspond to the period dividing circuit 15 in FIG. 1, and the analog switches SW1 and SW2 correspond to the electronic switches 19 and 20 in FIG. 1, respectively.

Circuit of diode D6, capacitor C12, resistor R35 and diode D7, capacitor C1
3. The circuit of the resistor R36 is designed to hold the maximum peak, and in the former circuit, the analog switch S
Figure 4 captured by W1

The maximum peak of the waveform [9] is held, and the maximum peak of the waveform of FIG. 4 [10] taken in by the analog switch SW2 in the latter circuit is held. The maximum peak held by the circuit of the former diode D6, capacitor C12, and resistor R35 is used as a reference value, and the maximum peak held by both circuits is used as the OP amplifier OP2-1.
And the voltage corresponding to the deviation is output.

Since the voltage corresponding to this deviation has a pulse shape, it is smoothed by the smoothing circuit of the capacitor C11 and the resistor R40. This smoothed voltage is the OP of the buffer
It is adapted to be applied to the diode D12 via the amplifier OP2-3, whereby the value of the current flowing through the resistor R61 changes, and the current flowing through the resistor R21 also changes. That is, the time constants of the resistors R21 and 61 and the capacitor C8 substantially change, and the transistors 301 and
Along with the alternating on / off time of 302, the slope of the sawtooth wave shown in FIG.

The change in the slope of the sawtooth wave output from the pin number 7 of this IC3 causes the OP amplifier OP2-4 to operate.
Output timing has changed, IC3 pin numbers 12, 1
The half cycle in one cycle of ON / OFF output from 3 is
The first half time is divided at a predetermined ratio longer than the second half time, and the acquisition time of the analog switches SW1 and SW2 is changed.

The diode D12 is a clamp diode and is connected in order to prevent the voltage of the OP amplifier OP1-2 from rising when the power is turned on and the oscillation frequency of the IC3 from dropping below a necessary level.

As is clear from the above description, the circuit of the diode D6, the capacitor C12 and the resistor R35, the circuit of the diode D8, the capacitor C13 and the resistor R36 are shown in FIG.
Corresponding to the peak detection circuits 17 and 18 of
The circuit of the OP amplifier OP1-2, OP amplifier OP2-3, the capacitor C11, and the resistors R37 to R40 corresponds to the error amplification circuit 16 of FIG. 1, and the capacitor C8 and the resistor R21 are the capacitors 22 and 24 of FIG. It corresponds to each.

The OP amplifier 304 of IC3 is designed to alternately turn off the transistors 301 and 302. When the voltage of the battery 2 rises for some reason, for example, overcharging, and exceeds the zener voltage of the constant voltage diode ZD4, the constant voltage diode ZD4 as shown in FIG.
Turns on. Therefore, the potential of pin number 2 of IC3 rises.

FIG. 8 shows the situation at this time. The level L2 in FIG. 8A corresponds to the potential of the pin number 2 of the IC3, and the level L2 rises as shown by the solid line.
As the level L2 rises, the intersection with the sawtooth wave changes, and as shown by the solid lines in FIGS. 8 (2) and 8 (3), the output widths of the transistors 301 and 302, that is, IC3.
The output width of each of the pin numbers 12 and 13 is reduced. The dotted line in FIG. 8 shows the state before the voltage rise.

As a result, the FET transistor 4 and the FET
The on-time width for alternately turning on the transistor 5 is reduced, the supply voltage to the vibration type compressor 1 is lowered, and the valve striking of the vibration type compressor 1 is prevented.

On the other hand, when the voltage of the battery 2 is equal to or lower than the predetermined voltage, the constant voltage diode ZD4 is off, and the potential of the pin number 2 of the IC3 is determined by the resistance ratio between the resistor R22 and the thermistor TH2.

The thermistor TH2 detects the ambient temperature of the refrigerator. When the ambient temperature of the refrigerator falls, the resistance value of the thermistor TH2 rises, and the pin number 2 of the above IC3
Potential, that is, the level L2 rises.

Therefore, as in the case of the above description, the output widths of the pin numbers 12 and 13 of the IC 3 are reduced, and when the ambient temperature of the refrigerator is lowered, the valve striking of the vibration type compressor 1 is prevented. To be done.

FIG. 9 is an explanatory view of the constituent parts of another embodiment for preventing valve hitting. In the case of the same drawing, the voltage of the battery 2 (more precisely, the voltage of the battery 2 passing through the diode D1) is directly applied to the resistor R22. Others are the same as those in FIG. The potential of the pin number 2 of the IC 3, that is, the level L2 changes in accordance with the voltage change of the battery 2. When the voltage of the battery 2 becomes high, the IC
The potential of the pin No. 2 of 3 becomes high, and the level L2 of FIG. 8 (1) rises. As a result, similarly to the case described above, the occurrence of valve striking of the vibration type compressor 1 is prevented in advance.

The battery monitor circuit 51 is connected for protection when the voltage of the battery 2 drops.
When the voltage of the battery 2 drops below a predetermined voltage, O
The output of the P amplifier OP2-1 becomes H level, and IC2,
The operation of the IC3 is stopped. At this time, the lamp LED2 is turned on to display the drop in the battery voltage.

When the temperature becomes higher than the temperature set by the temperature setting volume VR1, the thermo control circuit 52
The operations of IC2 and IC3 are stopped. That is, when the thermistor TH1 for detecting the temperature in the refrigerator detects the temperature below the temperature set by the temperature setting volume VR1,
The output of the P amplifier OP2-2 becomes L level, and IC2,
The IC3 is operated. When the thermistor TH1 which detects the temperature in the refrigerator detects the temperature equal to or higher than the temperature set by the temperature setting volume VR1, the output of the OP amplifier OP2-2 becomes H.
When the level is reached, the operations of IC2 and IC3 are stopped and the battery 2 is conserved.

In the above configuration, the operation of the circuit except the battery monitor circuit 51 and the thermo control circuit 52 is the same as that of the configuration of FIG. 1, so the description of the operation is omitted.

As the current detecting means for detecting the current flowing in the vibration type compressor 1, in addition to the shunt resistor 8 described above, a current transformer using a Hall element, a drain-source resistance Vds of an FET transistor, and a fuse are used.

[0075]

As described above, according to the present invention, the ratio between the peak detection time in the first half and the peak detection time in the latter half is always constant regardless of the fluctuation of the resonance frequency due to the load fluctuation of the vibration type compressor. By keeping the peak detection time of the first half longer than the peak detection time of the latter half while keeping the maximum peak, the maximum peaks appearing in the first half and the second half of the current waveform flowing through the vibration type compressor can be detected. It will be possible to detect it with certainty. Therefore, it is possible to generate an AC voltage having a frequency such that the maximum peak in the first half and the maximum peak in the second half are equal to each other, and the vibration type compressor can always be driven with maximum efficiency.

When the DC voltage is high and the ambient temperature of the refrigerator is low, the voltage supplied to the vibration type compressor is lowered, and the valve striking of the vibration type compressor 1 is prevented.

[Brief description of drawings]

FIG. 1 is a configuration of an embodiment of a power supply device for a vibration type compressor according to the present invention.

FIG. 2 is a configuration of an embodiment of a polarity inversion circuit.

FIG. 3 is an explanatory diagram of detection of a maximum peak in each waveform.

FIG. 4 is an operation waveform explanatory diagram.

FIG. 5 is a circuit diagram of a specific example of a power supply device for a vibration type compressor according to the present invention.

6 is a circuit diagram of a specific example of the frequency tracking circuit, the battery monitor circuit, and the thermo control circuit used in FIG.

FIG. 7 is an explanatory diagram of a potential change of pin number 2 of IC3 with respect to an increase in DC voltage.

FIG. 8 is an explanatory diagram of an output width change.

FIG. 9 is an explanatory view of a configuration part of another embodiment for preventing valve striking.

[Explanation of symbols]

 1 Vibration type compressor 2 Battery 3 Polarity inversion circuit 4,5 FET transistor 6 Inverter circuit part 7 Control part 8 Shunt resistance 9 Switching element control circuit 10 Frequency follow-up circuit 14 Variable oscillator 15 Period division circuit 16 Error amplification circuit 17, 18 peak Detection circuit 19, 20 Electronic switch 38 Voltage detection circuit 39 Atmosphere detection unit

Claims (5)

[Claims] 1. A direct current power supply, a polarity reversing circuit for reversing the polarity of the direct current power supply, an inverter circuit section which is provided with two switching elements and which converts direct current into alternating current by alternate switching, and controls the inverter circuit section. In a power supply device for a vibration type compressor including a control unit, a current detecting means for detecting a current flowing through the vibration type compressor is provided, and the control unit includes a variable oscillator whose oscillation frequency is variable, and the variable oscillator. A period dividing circuit that divides one cycle of the oscillating frequency at a predetermined ratio in which the first half time is longer than the second half time, and an electronic switch that captures the current waveform flowing in the current detecting means in the first half second half division time output by the cycle dividing circuit. , The peak detection circuit that detects the maximum peak of the current waveform captured through the electronic switch and the peak detection circuit. A frequency tracking circuit having an error amplification circuit that compares the two generated peaks and changes the oscillation frequency of the variable oscillator according to the difference, and a switching element that alternately switches the switching element at the oscillation frequency of the variable oscillator. And a voltage detection circuit for detecting the voltage of the DC power supply and varying the output width of the variable oscillator based on the DC voltage so that the current flowing through the vibration type compressor is minimized. A power supply device for a vibration type compressor, characterized in that the vibration type compressor is driven by an AC power supply of various frequencies to improve the efficiency of the vibration type compressor and to prolong the life of the vibration type compressor. 2. The vibration type device according to claim 1, wherein the voltage detection circuit includes a constant voltage diode, and the output width of the variable oscillator is variable when the DC power supply voltage exceeds a predetermined voltage. Power supply for compressor. 3. The power supply device for a vibration type compressor according to claim 1, wherein the voltage detection circuit is configured to vary an output width of the variable oscillator in proportion to a DC power supply voltage. 4. A direct current power source, a polarity reversing circuit for inverting the polarity of the direct current power source, an inverter circuit section which is provided with two switching elements and which converts direct current to alternating current by alternate switching thereof, and controls the inverter circuit section. In a power supply device for a vibration type compressor including a control unit, a current detecting means for detecting a current flowing through the vibration type compressor is provided, and the control unit includes a variable oscillator whose oscillation frequency is variable, and the variable oscillator. A period dividing circuit that divides one cycle of the oscillating frequency at a predetermined ratio in which the first half time is longer than the second half time, and an electronic switch that captures the current waveform flowing in the current detecting means in the first half second half division time output by the cycle dividing circuit. , The peak detection circuit that detects the maximum peak of the current waveform captured through the electronic switch and the peak detection circuit. A frequency tracking circuit having an error amplification circuit that compares the two generated peaks and changes the oscillation frequency of the variable oscillator according to the difference, and a switching element that alternately switches the switching element at the oscillation frequency of the variable oscillator. A control circuit, an atmosphere temperature detecting unit that detects the atmosphere temperature, and varies the output width of the variable oscillator based on the atmosphere temperature, and a frequency that minimizes the current flowing through the vibration type compressor. The power source device for a vibration type compressor is characterized in that the vibration type compressor is driven by the AC power source of (1) to improve the efficiency of the vibration type compressor and to prolong the life of the vibration type compressor. 5. A direct current power supply, a polarity reversing circuit for reversing the polarity of the direct current power supply, an inverter circuit section that is provided with two switching elements and that converts direct current into alternating current by alternate switching, and controls the inverter circuit section. In a power supply device for a vibration type compressor including a control unit, a current detecting means for detecting a current flowing through the vibration type compressor is provided, and the control unit includes a variable oscillator whose oscillation frequency is variable, and the variable oscillator. A period dividing circuit that divides one cycle of the oscillating frequency at a predetermined ratio in which the first half time is longer than the second half time, and an electronic switch that captures the current waveform flowing in the current detecting means in the first half second half division time output by the cycle dividing circuit. , The peak detection circuit that detects the maximum peak of the current waveform captured through the electronic switch and the peak detection circuit. A frequency tracking circuit having an error amplification circuit that compares the two generated peaks and changes the oscillation frequency of the variable oscillator according to the difference, and a switching element that alternately switches the switching element at the oscillation frequency of the variable oscillator. A voltage detection circuit for detecting the voltage of the DC power supply and varying the output width of the variable oscillator based on the DC voltage; and detecting the ambient temperature and varying the ambient temperature based on the ambient temperature. An atmosphere temperature detector that varies the output width of the oscillator is provided, and the efficiency of the vibration type compressor is improved by driving the vibration type compressor with an AC power source having a frequency that minimizes the current flowing through the vibration type compressor. A power supply device for a vibration type compressor, characterized in that the life of the vibration type compressor is increased.