JPH01255481A - Power source for vibrator - Google Patents

Abstract

PURPOSE:To prevent an element from overheat and collapse, by comparing the current of a ceramic vibrator with the current of a saturatable reactor to change an inductance. CONSTITUTION:A power source for vibrators is constituted so that an inverter circuit 12 is connected to a DC power source 11 and the first and second transistors(Tr) 16, 18 of a switching element are connected to the primary windings 15, 17 of a transformer 13 of the inverter circuit 12 to drive them by an oscillating circuit 19. A ceramic vibrator 22 and a first current detection circuit 23, which are connected in series, and the inductance coil 25 of a saturatable reactor 24 and a second current detecting circuit 27, which are connected in series, are connected in parallel to the secondary winding 21 of the transformer. Powers are inputted from the first and second current detection circuits 23, 27 into the operational amplifier 42 of a control circuit 41 respectively while the Tr 44 is driven by the output of the operational amplifier 42. According to this method, a power source 45 for controlling may be connected to the controlling coils 46, 47 of the saturatable reactor 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a power supply for a vibrator that vibrates a ceramic vibrator of an ultrasonic motor, for example.

(Prior art vf4) A conventional power supply for a vibrator of this type has a configuration shown in FIG. 7, for example.

In FIG. 7, 1 is a DC power source as a driving power source,
This DC power supply 1 is connected to an inverter circuit 2.

The positive terminal of the DC type rA1 is connected to the center of the primary winding 4 of the transformer 3, and one side of the negative winding 4 is connected to the DC power source 1 through the collector-emitter of the first transistor 5. The other side of the negative winding 4 is connected to the negative pole of the DC power supply 1 via the collector-emitter of the second transistor 6. This DC power supply 1 further includes:
An oscillation circuit 7 having a predetermined oscillation frequency fi is connected, and output terminals of the oscillation circuit 7 are connected to the base of the first transistor 5 and the base of the second transistor 6, respectively.

Furthermore, a ceramic vibrator 9 is connected to the secondary winding 8 of the transformer 3, and a coil 10 is also connected thereto.

Then, a voltage is applied from the DC power supply 1 to the oscillation circuit 7, and this oscillation circuit 7 connects the base of the first transistor 5 and the second
A base current is applied alternately to the bases of the transistors 6. As a result, current flows alternately to one side and the other side of the primary winding 4, and an alternating current voltage is induced in the secondary winding 8 of the transformer 3.

At this time, the coil 10 is adjusted so that the electrical resonance frequency h-2-π7T7 determined by the inductance 1- of the inverter circuit 2 and the coil 10 and the capacitance C of the ceramic sensor 9 is equal to the oscillation frequency light of the ceramic resonator 9. Adjust. The current induced in the secondary winding 8 causes the ceramic sensor 9 to vibrate.

(Problem to be Solved by the Invention) However, even if the coil 10 is adjusted at a certain temperature to match the electrical resonance frequency fε to the oscillation frequency fa,
As shown in FIG. 6, the capacitance C of the ceramic resonator 9 changes widely depending on the temperature, so the electrical resonance frequency of the circuit and the oscillation frequency foj of the ceramic resonator 9
fi changes quickly depending on the temperature, and if the operating environment conditions are wide, the load applied to the transistor 5.6 becomes a capacitive or inductive load, which increases the heat generation of the switching element 5.6 consisting of a transistor, etc., and there is a risk that it may be destroyed. There is a problem that there is.

The present invention has been made in view of the above problems, and aims to provide a power source for a cell that constantly matches the electrical resonance frequency of the circuit and does not heat or destroy switching elements. Objective 1゜ [Structure of the Invention] (Means for Solving the Problems) The power supply for a vibrator of the present invention comprises a DC power supply, an input end connected to the DC power supply, and converting the DC of the DC power supply into AC. an inverter circuit connected to the output end of the inverter circuit, a ceramic sensor connected to the output end of the inverter circuit, a first current detection circuit that detects the current flowing through the ceramic sensor, and an inductance connected to the output end of the inverter circuit. an inductor of a saturable reactor that varies the current, a second current detection circuit that detects the current flowing through the inductor, and a comparison circuit that compares the output of the first current detection circuit and the output of the second current detection circuit. and an inductance control circuit that varies the inductance of the inductor according to the output of the comparison circuit.

(Function) According to the present invention, power is supplied from a DC power source to an inverter circuit, and the inverter circuit converts the DC to AC to cause the ceramic vibrator to oscillate. Then, the current flowing through the ceramic resonator is detected by the first current detection circuit, the current flowing through the inductor is detected by the second current detection circuit, and the outputs of the first current detection circuit and the second current detection circuit are detected. Compare the boiled times,
According to the output of this comparison circuit, the inductance control circuit corrects the inductance of the inductor of the saturable reactor to correspond to the capacitance of the ceramic resonator.

(Example) Hereinafter, an example of the power supply for a vibrator of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a DC power source for driving, and an inverter circuit 12 is connected to this DC power source 11. In this inverter circuit 12, the positive terminal of the DC power source 11 is connected to the primary winding 14 of the transformer 13. Connected to the center of -Next Volume I!
The primary winding 15 on one side of the transformer 14 is connected to the negative pole of the DC power supply 11 via the collector-emitter of the first transistor 16 as a switching element, and the other side of the primary winding 14 of the transformer 13 The primary winding 17 is connected to the negative pole of the DC power supply 11 via the collector-emitter of a second transistor 18 as a switching element. Further, one oscillation circuit is connected to the DC power supply 11, and the bases of the first transistor 16 and the second transistor 18 are connected to this one oscillation circuit.

In the inverter circuit 12, the secondary winding 21 of the inverter 13 includes a ceramic resonator 22 and a first current detection circuit 23 connected in series, and a saturable reactor 24 connected in series. An inductor coil 25 as an inductor and a second current detection circuit 27 are connected in parallel 9, and the first current detection circuit 23 is connected to the secondary winding 2
1 and the ceramic vibrator 22, a voltage detection resistor 31 is connected in parallel to a capacitor 34 and a discharge resistor 33, which are connected in parallel via a diode 32. Further, the second current detection circuit 27 connects the secondary winding 2
1 and the inductor coil of the saturable reactor 24, a voltage detection resistor 3G is connected in series to a capacitor 39 and a discharge resistor 38 which are connected in parallel via a diode 37.

The connection point between the diode 32, discharge resistance 33, and capacitor 34 of the first current detection circuit 23 and the connection point between the diode 37, discharge resistance 38, and three capacitors of the second current detection circuit 27 are connected to the control circuit 41, respectively. The input terminals of the operational amplifiers 42, which function as comparators, are respectively connected.

The output terminal of this operational amplifier 42 is connected to the base of a transistor 44 via a resistor 43.
The emitter and collector of the saturable reactor 24 are connected to the control power source 45 and the control coils 46 and 47 of the saturable reactor 24, which are provided in series so as to cancel mutually induced voltages. Further, the control tllll power supply unit 45 has a half-wave rectifying diode 49 connected to a power supply winding 48 provided in the transformer 13, and further includes a smoothing capacitor 50.

Next, the operation of the above embodiment will be explained.

First, when power is supplied from the DC current 11111 to the oscillation circuit 19, a base current flows from the oscillation circuit 19 to the bases of the first transistor 16 and the second transistor 18, turning on the transistors 16 and 18 alternately. For example, first, when the first transistor 16 is turned on, a current flows through the path from the DC power supply 11 to the first primary winding 15 and the first transistor 16 . Next, the second transistor 1
A base current is applied to the base of the transistor 8 to turn on the second transistor 18, and at the same time, the base current of the first transistor 16 is extinguished to turn off the first transistor 16. Therefore, the current flowing in the path of the DC power supply 11i11, the first primary winding 15, and the first transistor 16 is changed to the DC power supply 11, the second primary winding 17, and the second transistor 1.
It flows through 8 routes. Therefore, the direction of the voltage induced in the secondary winding 21 is opposite, and by repeating these operations, alternating current is supplied to the ceramic vibrator 22. Then, by supplying alternating current, the ceramic resonator 2
2 is photographed.

Then, when the ceramic vibrator 22 is vibrating,
The voltage detection resistor 31 of the first current detection circuit 23 converts the current value of the ceramic resonator 22 into voltage and detects it, and the voltage detection resistor 36 of the second current detection circuit 27 detects the inductor coil of the saturable reactor 24. 25 current values are detected. The voltages detected by these voltage detection resistors 31 and 36 are compared by an operational amplifier 42, and the inductor coil 25
When the capacitance of the ceramic resonator 22 becomes higher than the inductance of the current and the voltage of the voltage detection resistor 31 increases, the output of the operational amplifier 42 increases.

As the output of the operational amplifier 42 increases, the base current increases, the current in the control windings 46 and 47 increases, and the inductance of the C inductor 25 decreases. As a result, the capacitor of the ceramic resonator 22 has a value corresponding to the inductance of the inductor coil 25. Conversely, when the capacitor of the ceramic sensor 22 becomes lower than the inductor coil 25, the current decreases, so the voltage of the voltage detection resistor 31 decreases, and the output of the operational amplifier 42 decreases. As the output of the operational amplifier 42 decreases, the base current of the transistor 44 decreases, and the control winding 46
．． 47 decreases and the inductance of the inductor coil 25 of the saturable reactor 24 increases. This causes the capacitor of the ceramic sensor 22 to correspond to the inductance of the inductor coil 25.

That is, as shown in FIG.
3 detects the current including the capacitance of the ceramic resonator 22, the second current detection circuit 27 detects the current including the inductance of the saturable reactor 24, compares the respective current values, and calculates the current value. Accordingly, the inductor of the saturable reactor 24 is varied to correspond to, for example, the capacitance of the ceramic sensor 22 that changes with temperature. In this way, as shown in FIG. 3, the current 1c containing the capacitor component and the current value IL containing the inductor component are made equal, and the ceramic resonator 22 is caused to resonate in parallel.
It vibrates.

In this way, even if the capacitance component of the ceramic resonator 22 changes due to temperature, the inductance always corresponds to the changed capacitance, thereby maintaining the co-formed state.

Further, the control ms source section 45 supplies the transformer 13 with 1tl! Winding 4
8, it can be directly connected to the DC power supply 11, or it can be set as a separate power supply.

The saturable reactor 24 can also be connected to the transformer 13 at the control coil 46 and 47 sides, and to the control power supply section 45 at the inductor coil 25.

Next, another embodiment of the vibrator power supply, which is a drive circuit for a two-phase ceramic motor, will be described with reference to FIG. 4.

An inverter circuit 51 that generates two-phase alternating current of a sine wave and a COS wave is connected to the DC power supply 1111, and a ceramic resonator 22, 22 and a movable A saturation reactor 24.24 is connected to the ceramic sensor 22.24.
A first current detection circuit 23 is connected to 22, and a second current detection circuit 27 is connected to the saturable reactor 24.24. Then, the first current detection circuit 23 and the second
The current detection circuit 27 is connected to an operational amplifier 42 that compares the outputs of the first and second current detection means 23 and 27. Further, the output terminal of the operational amplifier 42 is connected to the saturable reactor 24, 24 via the inductance control circuit 41.

In the inverter circuit 51, a COS wave output circuit is formed in the inverter circuit 12 shown in FIG. 1 via a phase circuit 52 that changes the phase by 90°, and
An n-wave output terminal, a COS-wave output terminal, and a common terminal are provided. The two saturable reactors 24.24 have four control coils 46.47.46.47 and a control power supply section 45.
connected in series. Furthermore, the discharge resistors 33, 38 of the first and second current detection circuits 23, 27 are provided in parallel with the capacitor 34, 39, as in the embodiment shown in FIG.

Next, the operation of the embodiment shown in FIG. 4 will be explained.

The oscillation circuit 19 of the inverter 51 turns on one transistor 16゜18 for sine wave AC output alternately, and the other for COS wave AC output via a phase circuit that changes the phase by 90 degrees. Transistors 16 and 18 are turned on alternately to generate a sine wave alternating current and a COS wave alternating current. And sin wave AC and C
Each O3 wave alternating current causes each ceramic vibrator 22, 22 to vibrate. At this time, the current added to the current flowing through the two ceramic oscillators 22.22 and the inductor coil 25 of the two saturable reactors 24.2.4
．． 25 is converted into a voltage by the first current detection circuit 23 and the second current detection circuit 27 and detected. Then, the output of the first current detection circuit 23, the output of the second current detection circuit 27, that is, the ml flowing to the ceramic vibrator 22, 22, and the saturable reactor 24.
．． By comparing the current flowing through the inductor coil 25.25 of 24 with the operational amplifier 42 and changing the base current of the transistor 44, the saturable reactor 24.2
The inductance of the inductor coil 25.25 of the saturable reactor 24.24 is changed by changing the current flowing through the control coil 46.47.46.47 of the saturable reactor 24.24. This causes the inductance to correspond to the changed capacitance of the ceramic vibrator 22.22.

Furthermore, the circuits shown in FIGS. 1 and 4 can be used not only for ultrasonic motors but also for cleaning machines and the like.

〔Effect of the invention〕

According to the present invention, the inductance of the saturable reactor is changed by comparing the current flowing through the ceramic resonator and the current flowing through the inductance of the saturable reactor to determine the change in the Yaya passitance of the ceramic resonator. Even if the capacitance of the ceramic resonator changes due to temperature, etc., the oscillation frequency fa of the ceramic resonator, the electrical resonance frequency, and the oscillation frequency f of the inverter circuit will always be maintained.
Since i is established and the load does not become an inductive or repulsive load, overheating and destruction of elements such as switching elements can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the vibrator power supply of the present invention, Fig. 2 is an explanatory diagram of a part of the same, Fig. 3 is a relationship diagram between inductance and capacitance, and Fig. 4 is another embodiment. Figure 5 is a diagram showing the relationship between the amount of vibration and frequency of the ceramic resonator, Figure 6 is a diagram showing the relationship between capacitance and temperature of the ceramic sensor, and Figure 7 is a circuit diagram showing a conventional example. be. 11...DC power supply, 12...Inverter circuit, 22...
Ceramic resonator, 23...first current detection circuit, 24
...Saturable reactor, 25...Inductor, 27...
2nd current detection circuit, 41...inductance control circuit, 42... comparison circuit.

Claims (1)

[Claims] (1) A DC power supply, an inverter circuit whose input terminal is connected to the DC power supply and converts the DC of the DC power supply into alternating current, a ceramic resonator connected to the output terminal of the inverter circuit, and a ceramic resonator connected to the output terminal of the inverter circuit. a first current detection circuit that detects a flowing current; an inductor of a saturable reactor that is connected to the output end of the inverter circuit and changes the inductance; a second current detection circuit that detects a current that flows through the inductor; It is characterized by comprising a comparison circuit that compares the output of the first current detection circuit and the output of the second current detection circuit, and an inductance control circuit that varies the inductance of the inductor according to the output of the comparison circuit. power supply for the vibrator.