JPH01255480A - Power source for vibrator - Google Patents

Abstract

PURPOSE:To prevent an element from overheat and collapse, by comparing the change of the capacitance of a ceramic vibrator through a comparison circuit to change the inductance of a variable inductance circuit. CONSTITUTION:A power source for vibrators is constituted of a DC power source 11 for driving and an external commutated inverter circuit 12, connected to the power source 11. In the inverter circuit 12, the DC power source 11 is connected to the center of the primary winding 14 of a transformer and one side of the primary winding 15 is connected to a switching element or a first transistor(Tr) 16 while the other side of the primary winding 17 is connected to a second Tr 18. An oscillating circuit 19 is connected to the DC power source 11 and the Trs 16, 18 are driven by the output of the oscillating circuit 19. A ceramics oscillating piece 22 and a variable inductance circuit 23 are connected to the secondary winding 21 of the transformer. The variable inductance circuit 23 is provided with a comparison circuit 24 for comparing the amount of capacitance of the oscillating piece with a reference in the comparing circuit and a saturatable reactor 25 connected in parallel to the secondary winding 21 while the Tr 37 is driven by the output of the comparison circuit 24.

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) A conventional power supply for a vibrator of this type has a configuration shown in FIG. 8, for example.

In the figure, 1 is a DC power supply as a driving power supply, and this DC type #! 1 is connected to the center of the primary winding 3 of the transformer 2, and one terminal of the negative winding 3 is connected to the collector of the first transistor 4. It is connected to the negative pole of the DC power supply 1 via the emitter.

The other terminal of the -order winding 3 is connected to the collector of a second transistor 5, and is connected to the negative electrode of the DC type [1] via the collector-emitter of the second transistor 5. Further, an oscillation circuit 6 having a predetermined oscillation frequency fi is connected to the DC power supply 1, and the output terminal of this oscillation circuit 6 is connected to a first transistor 4, respectively.
and connected to the base of the second transistor 5. These components constitute an inverter circuit 7 that converts the direct current of the direct current power supply 1 into alternating current.

Furthermore, a ceramic vibrator 9 and an inductor 10 for capacitance correction are connected to the secondary winding 8 of the transformer 2.

Then, a voltage is applied from the DC power supply 1 to the oscillation circuit 6, and the oscillation circuit 6 supplies current to the base of the first transistor 4 and the base of the second transistor 5 alternately. As a result, the first transistor 4 and the second transistor 5 are turned on alternately, and current alternately flows to one end and the other end of the -order winding 3, resulting in alternating current. At this time, in order to vibrate the ceramic resonator 9, the oscillation frequency fi of the oscillation circuit 6 is adjusted to the unique oscillation frequency light of the ceramic resonator 9, and the inductance L of the inverter circuit and the capacitance C of the ceramic resonator 9 are By setting the gap or the number of turns of the electrically resonant crimping transformer 2, or by setting the inductance value of the inductance 10, the oscillation frequency fa and the electrical resonant frequency are combined, and the inverter is operated in the state of 9-h = f; Activate circuit 7. The current induced in the secondary winding 8 causes the ceramic vibrator 9 to vibrate.

(Problem to be Solved by the Invention) However, by adjusting the gap or number of turns of the transformer 2 or setting the inductance of the inductor 10 at a certain degree i, the electrical resonance frequency can be adjusted to match the oscillation frequency C. Also, the capacitance C of the ceramic resonator 9 is the seventh
As shown in the figure, since the humidity changes greatly, the electrical resonance frequency of the circuit quickly collapses due to humidity, resulting in a capacitive or inductive load, which increases heat generation in switching elements such as transistors 4 and 5. There is a problem of destruction.

The present invention was made in view of the above problems, and the oscillation frequency fa of the ceramic resonator is always set to the resonant frequency f[
The purpose of the present invention is to provide a power supply for a vibrator that does not heat or destroy switching elements.

[Structure of the invention]

(Means for Solving the Problems) The power supply for a vibrator of the present invention includes a DC power supply, an inverter circuit whose input side is connected to the DC power supply and which converts the DC output of the DC F & power supply into AC, and a power supply of the inverter circuit. A ceramic resonator connected to the output side and imaged by the output of this inverter circuit, a comparator circuit that compares the capacitance of this ceramic resonator with the capacitance at resonance, and a saturable reactor. The invention further includes a variable inductance circuit that changes the inductance on the output side of the inverter circuit using the saturable reactor.

(Function) The present invention supplies power from a DC power source to an inverter circuit, and the frequency is adjusted by an oscillation circuit in the inverter circuit so that the inverter circuit oscillates at the unique oscillation frequency of the ceramic resonator, and the inverter circuit receives A ceramic resonator is generated by converting direct current to alternating current at this frequency.

Then, the comparator circuit compares the capacitance of the ceramic resonator with the reference in the comparator circuit, and the saturable reactor of the variable inductance circuit changes the inductance on the output side of the inverter circuit to adjust the capacitance of the ceramic resonator. Control to the corresponding inductance.

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

In FIG. 1, reference numeral 11 is a DC power source for driving, and a separately excited type inverter circuit 12 is connected to this DC type 11111.

In this inverter circuit 12, the positive terminal of the DC power supply 11 is connected to the center of the primary winding 14 of the transformer 13, and the primary winding 15 on one side of the secondary winding 814 is connected to a first transistor 16 as a switching element. connected to the collector of
The transistor 16 is connected through its collector and emitter to the negative electrode of the DC type 111j11. Further, the primary winding 17 on the other side of the primary winding 14 of the transformer 13 is connected to the collector of a second transistor 18 as a switching element, and the DC power supply 11 is connected to the collector-emitter of the transistor 18. Connected to negative pole. Further, an excavation circuit 19 is connected to the DC power supply 11, and an output terminal of the excavation circuit 19 is connected to the bases of the NPN transistor 16 and the transistor 18.

In the secondary winding 21 of the transformer 13 of the inverter circuit 12,
A variable inductance circuit 23 is connected to the ceramic resonator 22, and a comparison circuit 24 for comparing the capacitance of the ceramic resonator 22 with a reference in a comparison circuit 24 is connected to the variable inductance circuit 23. There is.

Further, the variable reactance circuit 23 has a saturable reactor 25 in parallel with the secondary winding 21 of the transformer 13.

As shown in FIGS. 2 and 3, this saturable reactor 25 has an inductance coil 26 connected in parallel with the secondary winding 21 of the transformer 13, and this inductance coil 26 is connected to the center leg 28 of the El core 27. The control coil is wound on both legs 29 and 30 of the EI cocoa 7 with an equal number of turns and is controlled so that the induced voltages cancel each other out.
Den II! 33 in series. and,
This saturable reactor 25 causes the El core 27 to magnetically saturate by applying a control current, which is a DC current, to the first control coil 31 and the second control coil 32 from the control m+ power supply 33, and the inductance coil 26 The inductance decreases rapidly as shown in FIG. That is, by varying the current of the control power source 33, the inductance of the inductance coil 26 can be varied.

Further, this control m+ power supply 33 is connected to a half-wave rectifying diode 35 to the power winding [134] provided in the transformer 13, and a smoothing capacitor 36 is connected in parallel to the power winding 34 via this diode 35. It is connected. This control m+ power supply 33 is connected to the control windings 31 and 32 of the saturable reactor 25 via the collector-emitter of an NPN transistor 31 as a control element, and the transistor 3
The base of 7 is connected to the output terminal of the comparison circuit 24.

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

First, when a voltage is applied to the inverter circuit 12 from the DC power supply 11!11, a base current is alternately passed from the excavation circuit 19 to the base of the first transistor 16 or the base of the second transistor 18. transistor 16
．． 18 turns on. First, when a base current is applied to the first transistor 1G and the first transistor 16 is turned on, a current flows from the DC type 11111 to the first transistor 16 of the primary winding 15 on one end side. Next, when a current is applied to the base of the second transistor 18 and the second 1-transistor 18 is turned on, a current flows from the DC power supply 11 through the path of the second transistor 18 of the primary winding 17 on the other end side. . This induces an alternating current voltage in the secondary winding 21, which in turn induces an alternating voltage in the secondary circuit of the transformer 13, causing the ceramic vibrator 22 to oscillate.

Then, the comparator circuit 24 compares the capacitance of the ceramic resonator 22 and In in the comparator circuit 24 . When it is determined that the capacitance amount has increased, the inductance of the saturable reactor 25 is decreased by increasing the base current of the transistor 37 and increasing the control current.

On the other hand, when the capacitance of the ceramic resonator 22 is decreasing, the base current of the transistor 37 is decreased, and the inductance of the saturable reactor 25 is increased by decreasing the t[I current.

In this way, even if the capacitance component of the ceramic resonator 22 changes due to temperature or the like, the inductance always corresponds to the changed capacitance.

Moreover, the control power source 33 is not limited to the case where the power supply winding 34 is provided on the transformer 13, and is not limited to the case where the control power source 33 is set by providing the power source winding 34 on the transformer 13. 11 or a separate power supply.

The saturable reactor 25 is provided with the control coils 31 and 32 on the transformer 13, and has a secondary winding I! The transformer 13 and the saturable reactor 25 can also be integrated by sharing the inductance coil 21 and the inductance coil 2G.

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.

An inverter circuit 41 that generates two-phase alternating current of a sine wave and a COS wave is connected to the DC power supply 11, and ceramic resonators 22 and 22 are connected to the output terminals of the inverter circuit 41 for the sine wave alternating current and the COS wave alternating current, respectively. A comparator circuit 24 is connected to these ceramic vibrators 22, 22. Moreover, the sine wave of the inverter circuit 41 and the C
The output terminal of the OS wave is connected to a variable inductance circuit 42 which is connected to the comparator circuit 24 and which varies the inductance based on the output of the comparator circuit 24 .

In the inverter circuit 41, a COS wave output circuit is formed in the oscillation circuit 19 of the inverter circuit 12 shown in FIG. 1 via a phase circuit 43 that changes the phase by 90°, and a sine wave output terminal A COS wave output terminal and a common terminal are provided. Inductance variable circuit 4
2, four control coils 31, 32, 31, 32 of two saturable reactors 25, 25 are connected in series to a control type 'm33. Further, the comparator circuit 24 compares the increase/decrease in capacitance of the two ceramic oscillators 22 and 22 with a reference within the comparator circuit 24, and changes the base current of the transistor 37.

Next, the operation of the embodiment shown in FIG. 5 will be explained.

Direct current from the DC power supply 11 is transferred to the oscillation circuit 19 of the inverter 41.
One transistor 16.18 is turned on alternately, and the other transistor 16.18 is turned on alternately through a phase circuit 43 that changes the phase by 90 degrees.
Generates n-wave alternating current and COS wave alternating current.

Then, each of the ceramic vibrators 22 and 22 is imaged by each of the sine wave alternating current and the COS wave alternating current.

At this time, the amount of capacitance of the two ceramic oscillators 22 is detected, and the increase or decrease thereof is compared with the reference in the comparison circuit 24, and the base current of the transistor 3I is changed, so that the amount of capacitance from the control 1lffl source 33 is The current is changed to change the inductance of the two saturable reactors 25.25. As a result, the ceramic resonator 2
2.Make the inductance correspond to the changed capacitance of 22.

Furthermore, the circuits shown in FIGS. 1 and 5 above can be used not only for ultrasonic motors but also for cleaners and the like.

〔Effect of the invention〕

According to the present invention, the comparison circuit compares changes in the capacitance of the ceramic resonator and changes the inductance of the variable inductance circuit, so even if the capacitance of the ceramic resonator changes due to temperature, etc. The oscillation mfa, the electrical resonance frequency, and the oscillation frequency fi of the inverter circuit are made equal, and there is no inductive or capacitive load, so overheating and destruction of the switching element can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the vibrator power supply according to the present invention, Fig. 2 is an explanatory diagram of the saturable reactor as above, Fig. 3 is an equivalent circuit diagram of the variable inductance circuit as above, and Fig. 4 is an explanatory diagram of the saturable reactor as above. Fig. 5 is a diagram showing the relationship between the saturation reactor and the control power supply, Fig. 5 is a circuit diagram showing another embodiment, Fig. 6 is a diagram showing the relation between the frequency of the ceramic resonator and the imaging m, and Fig. 7 is the relation between the temperature of the ceramic resonator and FIG. 8, which is a capacitance relationship diagram, is a circuit diagram of a conventional power supply for a vibrator. 11...DC power supply, 12...Inverter circuit, 22...
Ceramic resonator, 23...variable inductance circuit,
24...Comparison circuit, 25...Saturable reactor. Hiro

Claims (1)

[Claims] (1) A DC power source, an inverter circuit whose input side is connected to this DC power source and which converts the DC output of this DC power source to alternating current, and a ceramic vibration which is connected to the output side of this inverter circuit and is vibrated by the output of this inverter circuit. a comparator circuit that compares the capacitance of the ceramic resonator with the capacitance at resonance, and an inductance that has a saturable reactor and changes the inductance on the output side of the inverter circuit by the output of the comparator circuit. A power supply for a vibrator, characterized by comprising a variable circuit.