JPS601509Y2 - Magnetron drive power supply - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power supply device for driving a magnetron used in a microwave oven or the like.

In recent years, magnetrons have been widely used in high-frequency heating devices such as microwave ovens.

This magnetron exhibits low impedance near the operating point, and has the property that the anode current changes significantly with a slight change in the anode voltage. The fluctuation is large and may cause damage to the magnetron.

For this reason, power supply devices using leakage transformers have been put into practical use.

However, although it is possible to stabilize the anode current by using a leakage transformer that has constant current characteristics, it has the disadvantage that the oscillation output cannot be changed.
Furthermore, since the glue cage transformer for commercial frequencies is quite large, it sometimes becomes an obstacle to downsizing the high frequency heating device.

In order to solve the above-mentioned drawbacks, the present inventor has proposed a power supply device using a pulse width control transformer.

Here, the basic configuration of the pulse width control transformer is as shown in FIGS. 1 and 2.

In these figures, the magnetic core of the pulse width control transformer is
The magnetic core IA is a UI type magnetic core, and the magnetic core 1B is an EI type magnetic core.

The input winding 2 is commonly wound around one leg of the magnetic core IA and the middle leg of the magnetic core 1B, and the output winding 3 is wound around the other leg of the magnetic core IA.

Further, control windings 4A and 4B are provided on the side legs of the magnetic core IB, respectively, and both windings 4A and 4B receive a control current I.

When flowing, the magnetic flux generated in the path magnetic path consisting of the magnetic core IB becomes in phase, and the voltages induced in the respective windings 4A and 4B cancel each other due to the magnetic flux generated when the input voltage is applied to the input winding 2. are connected in series.

The pulse width control transformer as described above has control windings 4A, 4
By changing the DC control current I flowing through B, it is possible to change the magnetization state of the magnetic core 1B that cuts the path magnetic path, and as a result, the voltage pulse appearing across the load resistor R connected to the output winding 3 side can be changed. It has the characteristic that the width of the space can be controlled.

By the way, in order to put into practical use a magnetron drive power supply device using the pulse width control transformer as described above, especially a high frequency converter power supply device using semiconductors, it is necessary to incorporate a heater transformer to heat the magnetron cathode. In addition, a structure is required that is desirable from the viewpoint of wiring, and that allows each winding of the pulse width control transformer to be connected to an external circuit so as not to cause confusion during mounting.

In view of the above points, the present invention aims to provide a power supply device for driving a magnetron that is compact and has a structure suitable for mounting.

Embodiments of the magnetron drive power supply device according to the present invention will be described below with reference to the drawings.

FIG. 3 shows the mechanical structure of the embodiment, and FIG. 4 shows the electrical connections.

In these figures, the pulse width control transformer 10 has a UI-type magnetic core 1A that controls the main magnetic path, and an EI-type magnetic core 1B that controls the pass magnetic path. Control windings 4A and 4B are provided respectively, and an output winding 3 is provided on one leg of the UI type magnetic core 1A.

Further, an input winding 2 is commonly wound around the other leg of the magnetic core 1A and the middle leg of the magnetic core IB, and a part of the input winding 2 is also wound around the same leg as the output winding 3. .

That is, the input winding 2 adopts a bifilar winding so that a bush-pull connection type can be used as a converter circuit, and in order to obtain an appropriate degree of coupling between input and output.
It is composed of a main bifilar winding 2A commonly wound around the magnetic cores IA and 1B, and a sub bifilar winding 2B wound around the same leg as the output winding 3.

Note that an auxiliary power supply winding 5 is provided so as to be coupled to the input winding 2 as a control circuit power supply for flowing the control current I into the control windings 4A and 4B.

The pulse width control transformer 10 as described above includes fastening fittings 11A, IIB, screws 12. It can be assembled using a nut 13, and a heater transformer 14 is installed inside the tightening fitting 11A.
, the relay terminal block 15 is attached, and the clamping fittings 11A, 1
An external connection terminal board 16 is attached between the terminals 18.

In addition, an external connection terminal block 17 is provided on the outer surface of the tightening fitting 11B.
, a high voltage capacitor 18, and a diode 19 are provided.

The main bifilar winding 2A constituting the input winding 2
winding a1. a2 and the winding b1 of the sub-bifilar winding 2B
．． The connection points 20 and 21 with b2 are respectively made via the relay terminal block 15, and the connection points between the winding and the winding a2 are connected to the middle terminal piece 16A of the external connection terminal board 16. , further winding a1. The other end of b2 is connected to the input terminal pieces 16B and 16C of the external connection terminal board 16.

The control winding 4A. 4B are connected in series, one end of which is grounded together with one end of the auxiliary power winding 5.

Here, the clamping fittings 11A and 11B are used as grounding conductors, and therefore one terminal piece 17A of the external connection terminal block 17 is connected to the clamping fitting 11B as a common grounding terminal via the grounding piece 22. Connected.

External connection ends of the control windings 4A, 4B and the auxiliary power supply winding 5 are connected to the control terminal piece 17B and the auxiliary power supply terminal piece 17C of the external connection terminal block 17, respectively.

On the other hand, since high voltage is generated in the output winding 3, one end of the winding is connected to a grounding piece held between the fastening fitting 11A and the magnetic core 1A so that the end of the winding on the low voltage side does not pass near the high voltage side. 23
The other end is connected to one end of the high voltage capacitor 18.

The other end of this high voltage capacitor 18 is connected to a diode 19 and one end of the heater winding 14A of the heater transformer 14, and is further connected to the cathode (filament ).

Note that the primary winding 14B of the heater transformer 14 is connected in parallel to the input winding 2 of the pulse width control transformer 10.

According to the configuration of the above embodiment, the following effects can be achieved.

(1) Since the heater transformer 14 is mounted using a 1 mA fastening fitting for tightening the magnetic cores IA and IB of the pulse width control transformer 10, it is possible to downsize and conveniently implement.

(2) Since the high voltage capacitor 18 and diode 19 are arranged on the fastening fitting 11B, the pulse width control transformer 10
The wiring between the output winding 3 and the heater transformer 14 is easy, and by making these wirings in advance, the connection work with the magnetron 30 at the time of mounting can be extremely simplified.

(3) The input winding 2 is bifilar wound, and only the ends of the winding that need to be connected to the converter circuit are connected to the terminal board 16 for external connection.
Since the input winding 2 is pulled out from the outside, the connection between the input winding 2 and the external circuit can be easily made without error.

(4) Since the external connection ends of the control windings 4A, 4B and the auxiliary power supply winding 5 are drawn out to the external connection terminal block 17, these windings can be connected without error.

(5) By using the clamping fittings 11A and IIB as grounding conductors, one end of the output winding 3 can be connected to the other grounding piece 23.
It is convenient for electrical insulation.

FIG. 5 shows another embodiment of the present invention, in which a pulse width control transformer is also used for the heater transformer.

In this figure, the heater transformer 40 has a primary winding 41
, a secondary winding 42 as a heater winding and a control winding 43A
, 43B, the pulse width control transformer having
Its structure is basically similar to that shown in FIG.

In this case, the power on the secondary winding 42 side can be controlled by the DC control current I' flowing through the control windings 43A and 43B, and the heating power of the cathode of the magnetron 30 can be stabilized.

Note that the other configurations are the same as those in FIGS. 3 and 4.

As described above, according to the present invention, a magnetron driving power supply device having a structure that is small and suitable for mounting is obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the basic configuration of a pulse width control transformer, Fig. 2 is a circuit diagram showing its electrical connection, and Fig. 3 is an exploded view showing an embodiment of the magnetron drive power supply device according to the present invention. A perspective view, FIG. 4 is a circuit diagram showing the electrical connection,
FIG. 5 is a circuit diagram showing another embodiment of the present invention. mA, IB...Magnetic core, 2...Input winding, 3...Output winding, 4A, 4B...Control winding, 5... ...Auxiliary power supply winding, 10...
・Pulse width control transformer, 11A, IIB...
Tightening fittings, 12... Screws, 13... Nuts, 14... Heater transformers, 15...
...Terminal block for relay, 16...Terminal block for external connection, 17...Terminal block for external connection, 18...
・High voltage capacitor, 19...Diode, 22
．． 23... Grounding piece.

Claims (2)

[Scope of utility model registration request] (1) UI type magnetic core that controls the main magnetic path and EI that controls the pass magnetic path
a type magnetic core, an input winding commonly wound around the legs of both magnetic cores,
A pulse width control transformer having an output winding wound around the other leg of the UI type magnetic core and control windings provided on both legs of the EI type magnetic core to change the magnetization state is assembled by tightening with a fastener. A power supply device for driving a magnetron, further comprising: a heater transformer attached to the fastener, and a primary winding of the heater transformer connected in parallel to an input winding of the pulse width control transformer. (2) The power supply device for driving a magnetron according to claim 1, wherein the heater transformer is constituted by a pulse width control transformer.