JPS6024602B2 - High frequency oscillator - Google Patents

Description

[Detailed Description of the Invention] This invention simplifies the circuit configuration, reduces weight and size,
Furthermore, the present invention relates to a high-frequency oscillation device whose oscillation operation is extremely stable.

Conventionally, in ultrasonic cleaning machines that generate ultrasonic vibrations in cleaning liquid to perform cleaning, high-frequency oscillations (1 Hz to 50 K) are used.
A high-frequency oscillation device that supplies high-frequency power to a load with a high frequency ratio (ratio) generally has a configuration as shown in FIG. 1 or 2.

That is, Fig. 1 shows a type that uses a high-frequency transformer T for matching to generate high-frequency oscillation, and the power terminal I on the tenth side is connected to the intermediate tap of the primary winding of the high-frequency transformer T, and the first and second By alternately conducting the transistors Q, Q2, a rectangular wave voltage as shown in Figure 3a is applied to both ends of the primary winding of the high frequency transformer T, and the secondary winding of the high frequency transformer T is The high frequency power of the load voltage as shown in FIG. 3b and the load current as shown in FIG. 3c are coupled to the load RL' through a matching capacitor C connected to the line. Note that the first or second diode D or D2 connected in parallel to the first or second transistor Q or Q2 is provided to flow a delayed current at the time of load fluctuation. To explain the case where the first transistor Q, changes from on to off, and the second transistor Q2 changes from off to on, the current flowing through the first transistor Q, when it is on, flows through the power supply terminal 1 on the positive side and the high frequency transformer. The current is flowing in the path of the primary winding of T, the first transistor Q, and the power supply terminal 1' on one side, and when the lagging current is flowing, the first
1 of the high frequency transformer T when the transistor Q is turned off.
Since the potential at one end A of the next winding is higher than the potential at the other end B, the lagging current on the primary side of the high frequency transformer T
Flows from one end A of the current to the end B of the high frequency transformer T via the second transistor Q2 and the first diode D. That is, by passing a delayed current through the first and second diodes D, D2, the first and second transistors Q, Q2
This prevents reverse voltage from being applied to the On the other hand, Fig. 2 shows an OTL type high-frequency oscillator, in which the first and second transistors Q, Q2 are turned on alternately as in the case of Fig. 1, and a series circuit of a matching capacitor C and a load RL is connected. Apply a square wave voltage.

Then, when the first transistor Q is turned on, the energy stored in the matching capacitor C and the load RL is discharged when the second transistor Q2 is turned on, and high frequency power is applied to both ends of the load RL. In addition, the first and second diodes D, D2 connected in parallel to the first and second transistors Q, Q2, respectively,
This is to bypass the transistors Q, , Q2 so that no reverse voltage is applied to them. However, in both of the above devices, two switching transistors Q, Q2 are required, which complicates the circuit configuration, and due to series resonance, the matching between the load RL and the matching capacitor C is extremely difficult. It is difficult, circuit design is not easy, and the oscillation operation is unstable.

Furthermore, the use of the high frequency transformer T in the apparatus shown in FIG. 1 makes the entire apparatus larger and heavier, resulting in higher costs. Next, we will explain in detail FIG. 4, which shows the basic wiring diagram of the present invention, which has a simplified circuit configuration, is lightweight, and has stabilized oscillation operation, taking into account the various drawbacks of the conventional technology. .

In Fig. 4, E is a DC power supply, RL, L, and S are loads consisting of inductances connected in series across the DC power supply 8, switching elements such as current-limiting reactors and transistors, and C is parallel to the load RL. The oscillation capacitors C2 and R are connected in series and are connected in parallel to the current limiting reactor L, respectively, and the capacitor and resistor for azosoba (surge absorption) are connected. D3 prevents the application of reverse voltage to the switching element S. bypass diode, PD
is a pulse generator connected to a control terminal such as a base of a transistor in the switching element S.

Next, the operation of the connection diagram will be explained with reference to FIGS. 5 and 6.

First, as shown in FIG. 6a, when a pulse signal is applied from the pulse generator PD to the control terminal of the switching element S, the switching element S becomes conductive, and as shown in FIG.
As shown by the arrow direction in the figure, a current flows from the DC power supply E to the oscillation capacitor C and the current limiting reactor L, and a current also flows to the load RL.

Therefore, as shown in Fig. 6b, the voltage across the load RL rises as shown by the solid line, and the current flows as shown in the broken line in Fig. 6, and as shown in Fig. 6c. ,
The voltage across the ocular flow reactor L decreases. At this time,
The current flowing through the switching element S and the voltage across it have waveforms as shown in FIGS. 6d and 6e. next,
As shown in Fig. 6a, when the pulse signal applied to the switching element S falls at time t2, the switching element S becomes non-conductive, and oscillation occurs as shown in the arrow direction of Fig. 5b. The energy stored in the capacitor C is supplied to the load RL, causing resonance, and the energy of the current limiting reactor L is released via the resistor R and the capacitor C2.

Therefore, the voltage across the load RL decreases as shown in Fig. 6b, and the energy of the current limiting reactor L is reversed and the resistor R and capacitor C2 It gets absorbed. Then, at time t3, the voltage across the oscillating capacitor C becomes zero, and as shown by the arrow direction in FIG. Figure 6b
As shown in the figure, a negative voltage is supplied, and as shown in Figure 6C, the energy of the current limiting reactor L is dissipated, and at the time 4 shown in Figure 6, the voltage of the oscillation capacitor C returns to its original value. Returns to polarity. Then, as shown in FIG. 6a, a pulse signal is outputted from the pulse generator PD to the time bond, and the same operation as described above is sequentially repeated. At this time, by making the inductance of the current limiting reactor L almost equal to the inductance of the load RL, a positive half wave (from time t3) and a negative half wave (from time t3) of the voltage applied to the load RL are created. At time t4), the pressure is almost the same as that at time t4), and the load flower L is operated efficiently. Now, if the current limiting reactor L is short-circuited, charging of the oscillation capacitor C will be completed in a short time, the positive half wave and the negative half wave of the load RL will not be the same, and furthermore, the switching An excessive current also flows through the element S, and the switching element S is damaged. However, in this invention, from the current limiting reactor L', the load RL
It operates efficiently and protects the switching element S. In addition, the switching element S in the above wiring diagram
The same effect can be obtained not only with transistors but also with thyristors, and the application is not limited to the ultrasonic cleaners mentioned above.
This can be applied when the load RL is an inductance load.

Further, the series circuit of the absorber resistor R of the current limiting reactor L and the capacitor C2 may be a resistor-only circuit, but in that case, the capacitance becomes large. This invention provides a device that reduces power loss and operates more economically in the device shown in FIG. This will be explained in detail with reference to figures.

In the figure, the same symbols as in Figure 4 indicate the same things,
The resistor R and capacitor C2 for the absorber of the current limiting reactor L are not provided, and the secondary winding L' is provided in the current limiting reactor L, and the secondary winding L' is connected to the feedback diode ○4.
It is connected to the DC power supply E via.

The basic operation is exactly the same as in the case shown in Fig. 4, but since a voltage is induced in the secondary winding L' by the current limiting reactor L and fed back to the power supply via the feedback diode D4, Power loss is reduced.

As described above, according to the high frequency oscillator of the present invention, a series circuit of an inductance load, a current limiting reactor, and a switching element such as a transistor is connected to both ends of a DC power supply, and an oscillation capacitor is connected in parallel to the load. , a secondary winding is provided in the current limiting reactor, and the secondary winding is
By connecting to the DC power supply via a feedback diode, only one switching element is required, the circuit configuration is simplified, the number of parts is reduced, and it is economical.

Moreover, since the load and the oscillation capacitor perform resonant operation, the oscillation operation is extremely stable, and the output characteristics are also stable due to the current limiting reactor, making the circuit design very easy. Furthermore, there is no need for a high frequency transformer, resulting in smaller size, lighter weight, and lower cost. Furthermore, power loss can be reduced, making it more economical.

[Brief explanation of the drawing]

Figures 1 and 2 are wiring diagrams of a conventional high-frequency oscillator,
Figure 3 is a waveform diagram of voltage or current at each part in Figure 1.
Figure 5 is a basic wiring diagram of the high frequency oscillator of the present invention, Figure 5 is an explanatory diagram of the operation of Figure 4, Figure 6 is a voltage or current waveform diagram of each part of Figure 4, and Figure 7 is the first diagram of the present invention. It is a wiring diagram of an example. E...DC power supply, C. ...Oscillation capacitor, RL・
...Load, L...Current limiting reactor, S...Switching element, L'...Secondary winding, D4...Feedback diode. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A series circuit of an inductance load, a current limiting reactor, and a switching element such as a transistor is connected to both ends of a DC power supply, an oscillation capacitor is connected in parallel to the load, and a secondary winding is provided to the current limiting reactor. The high frequency oscillation device is further characterized in that the secondary winding is connected to the DC power supply via a feedback diode.