JPS587620Y2 - Ferro-resonant transformer voltage stabilizer - Google Patents

Description

[Detailed description of the invention] The present invention relates to ferro-resonant transformers used in power supply circuits, etc., and in particular aims to improve the stability of the output voltage of the multi-output terminals of high-frequency ferro-resonant transformers. .

Ferro-resonant transformers generate a lot of heat due to large losses such as hysteresis loss and copper loss, and therefore, depending on the core material, the saturation magnetic flux density Bm decreases due to an increase in core temperature, resulting in a decrease in output voltage.

Furthermore, the iron resonant transformer has the disadvantage that the output voltage fluctuates due to fluctuations in the frequency of the AC power source and the load.

As a means to improve this drawback, a voltage stabilizing circuit as shown in FIG. 1 has been proposed (Japanese Patent Application No. 52-8214
8).

In FIG. 1, 1 is an AC power supply, 2 is a ferro-resonant transformer having a human-powered winding 3 wound around an iron core, and a resonant output winding 4;
is a resonant capacitor, the AC power supply 1 is connected to the input winding 3 of the iron resonant transformer, the output winding 4 and the resonant capacitor 5 form a resonant circuit, and the output is rectified by the rectifier circuit 6. It is smoothed by a capacitor 7 and supplied to a load 8.

Reference numeral 9 denotes a saturable reactor having a controlled winding 10 and a control winding 11, and a control power supply circuit 1 that detects voltage fluctuations of the load 8.
The output of No. 2 is applied to the control winding 11 to stabilize the voltage.

FIG. 2 shows an example of the structure of the saturable reactor 9 described above.

Points a and a' in the figure are connected to points a and a' in FIG.

Therefore, the controlled winding 10a. A resonant current due to resonance between the resonant output winding 4 and the resonant capacitor 5 of the iron resonant transformer flows through 10a'.

Magnetic flux φ1 is generated by flowing DC current 11 from control power supply 12 to control winding 11 wound around the center leg of core 13 of the saturable reactor, and magnetic flux φ generated by increasing or decreasing 1
1 changes, the controlled windings 10a, 10a
The inductance Laa' changes as shown in FIG.

That is, when the DC current 11 is small, the controlled winding 10 a
, 10 a' has a large inductance Laa', and ■1
As becomes larger, the inductance becomes smaller.

In FIG. 1, if the inductance of the controlled winding 10 of the supersaturated reactor 9 is large, both ends a, a
If the inductance is small, the voltage between a and a' will be low.

Therefore, by connecting the output winding of the ferro-resonant transformer 2 and the controlled winding of the saturable reactor in series so that the voltages add to each other, the output voltage of the ferro-resonant transformer is equal to the inductance of the controlled winding of the saturable reactor. It can be set freely by increasing or decreasing.

That is, it detects the output voltage fluctuations due to load fluctuations, the temperature rise of the ferro-resonant transformer, and the frequency fluctuations of the AC power supply, and changes the output voltage by changing the inductance of the controlled winding of the saturable reactor. Stability can be measured.

However, with the configuration shown in Figure 1, only a single output voltage can be stabilized, and if multiple output voltages are to be stabilized, multiple saturable reactors and control power supplies are required, and in that case multiple The disadvantage is that the circuit becomes complicated because the output voltage of each must be detected individually.

The present invention aims to solve such drawbacks, and consists of a ferro-resonant transformer having a plurality of output windings, a saturable reactor consisting of a control winding and first and second controlled windings, and a control power supply. In the resonant circuit consisting of the inductance of the resonant winding of the iron resonant transformer and the resonant capacitor, the first
The controlled windings of the ferro-resonant transformer are connected in series, each of the plurality of output windings of the ferro-resonant transformer is connected in series with one of the first and second controlled windings, and the control power source is connected to the output of the ferro-resonant transformer. No. 1
By detecting one and passing a control current through the control winding, the inductance of the first controlled winding is changed to make the voltage across the first controlled winding variable. The structure is such that the voltage is added to the output winding according to the number of windings.

FIG. 4 shows an embodiment of the present invention.

In this figure, parts having the same numbers and symbols as those in FIG. 1 are the same or have the same functions.

The ferro-resonant transformer 2 has a plurality of output windings 4 a and 4 b.
, 4C, and the saturable reactor 9 has a first controlled winding 10a, one or more (two in the figure) second controlled windings 10b, an IOC and one control winding. It has a line 11.

14 is a DC power supply, 15 is an oscillation circuit, 16 is a drive circuit, and 17 is a switching transistor.

The oscillation circuit 15 generates a high frequency pulse (15~20 KH
The switching transistor 17 is driven by the drive circuit 16, and a high-frequency AC voltage is applied to the input winding 3 of the ferro-resonant transformer 2.

The resonant winding 4 and the resonant capacitor 5 constitute a parallel resonant circuit, and the first controlled winding 10a of the saturable reactor 9 is connected in series in this parallel resonant circuit, and a plurality of separate windings are simultaneously connected. The second controlled windings 10b, 10C are connected in series with the other output windings 4b, 4C of the ferro-resonant transformer, respectively, and the voltage across the first controlled winding 10a is proportional to the voltage across the first controlled winding 10a. a plurality of induced second controlled windings 10b,
10C is connected so that the voltage across each end of each of the output windings 4b and 4C of the ferro-resonant 1-lance is added to the voltage across each of the other output windings 4b and 4C.

An example of the saturable reactor 9 shown in FIG. 4 is shown in FIG.

In the figure, first controlled windings 10 a and 10 a'
The inductance changes as shown in FIG. 3 depending on the DC current (1) supplied from the control power source 12.

Controlled windings 10a, 10b, 1 in FIG.
The number of windings of each output winding is 4 a , 4 b , 4
For example, 10 a > 10 b > depending on the number of windings of C.
10C shall be selected.

The first controlled winding 10 a is inserted into the resonant circuit of the ferro-resonant transformer, and the voltage across it is expressed by the equation (1) (1) where e is the voltage, N is the number of turns, and dφ is Change in magnetic flux φ, d
t is the change in time t, t is the change in current, and L is the inductance value.

That is, when the inductance value changes, the voltage across the first controlled winding 10a changes.

Since a voltage with the same polarity as the resonant winding 4 is generated at both ends of the first controlled winding 10a inserted in series in the resonant circuit of the ferro-resonant transformer, the resonant capacitor 5 is connected to the resonant winding. 4 and the voltage across the first controlled winding 10a are generated.

Further, a change dφ in the magnetic flux φ caused by a change di in the resonant current flowing through the first controlled winding 10a interlinks with the second controlled winding 10b and the IOC.

Therefore, due to a change in the resonant current of the first controlled winding 10a, the magnetic flux interlinking with the second controlled winding 10b and the IOC changes, and due to electromagnetic induction, the second controlled winding 10b
, an electromotive force proportional to each turn ratio is generated in the IOC, for example, 10 a > 10 b > 10 c.

Output windings 4 a , 4 b , 4 C of iron resonant transformer
For example, the turns ratio of the controlled winding is determined as 4 a > 4 b > 4 C, and the turns ratio of the controlled winding is determined as 10 a > 10 b > 10 C according to each turns ratio. .

The voltage generated across the controlled winding 10b is connected to the output winding 4b of the ferro-resonant transformer so as to have the same polarity, and the voltage generated across the controlled winding 10C is connected to the output winding 4b of the ferro-resonant transformer. They are respectively connected to the output winding 4C so as to have the same polarity.

Therefore, as shown in FIG. 5, the controlled windings 10a, 10 are
Since the inductance values of b and 10 C change, the output of each ferro-resonant transformer can be changed according to the respective turns ratio.

The operation of the circuit shown in FIG. 4 is as follows.

An oscillation circuit 15, a drive circuit 16,
The switching transistor 17 operates to apply a high frequency AC voltage of 15 to 20 KHz to the input winding 3 of the ferro-resonant transformer 2.

The resonant winding 4 and the resonant capacitor 5 constitute a parallel resonant circuit, and the voltage V across the resonant winding 4 at this time is expressed by the following equation.

V−V7・π・f−A−N−Bm (2) where f is the frequency, A is the cross-sectional area of the core, N is the number of turns, and Bm is the maximum magnetic flux density of the core.

That is, a resonant current flows due to the parallel resonance between the resonant winding 4 and the resonant capacitor 5, and the core in which the resonant winding 4 is arranged is excited to the maximum positive and negative magnetic flux density of the B-H curve. .

As shown in FIG.
The resonance current of a and the load current flow.

The output windings 4 b and 4 C are arranged in close connection with the core on which the resonance winding 4 is arranged.

Therefore, the output voltage of the output winding 4a is stabilized, and the output voltage of each output winding 4b, 4C is also stabilized.

Also, since the B-H curve is a curve near the maximum positive and negative magnetic flux densities, each output winding 4a.

The maximum magnetic flux density Bm of the core in equation (2) changes slightly due to changes in the load of 4b and 4C.

Therefore, due to any load fluctuation, each output winding 4 a
, 4 b , and 4 C also vary depending on their turns ratio.

Since a resonant current flows through the first controlled winding 10a inserted into the resonant circuit of the resonant winding 4 and the resonant capacitor 5, a voltage is generated at both ends aa' of the first controlled winding 10a.

Further, alternating current voltages proportional to the ratio of the number of turns to the first controlled winding 10 a are induced in the second controlled windings 10 b and 10 C, respectively.

These induced voltages are 10 a > 10 b > 10C.

When the DC current applied to the control winding 11 from the control power supply 12 that detects the voltage fluctuation of the load 8 is increased, the inductance of the first controlled winding 10a becomes smaller and the voltage across it decreases.

Therefore, the voltage induced in the second controlled windings 10 b and 10 C also decreases according to their turns ratio.

Conversely, if the DC current supplied to the control winding 11 is reduced,
The inductance of the first controlled winding 10a increases, and the voltage across it increases.

Therefore, the voltage induced in the second controlled winding 10b and the IOC also increases in accordance with the turn ratio with respect to the first controlled winding 10a.

Therefore, as shown in the figure, for example, the output voltage of the output winding 4C is detected by the control power supply 12, while the symbols a, a', l), l)', c, and c' in FIG. If the output of the output winding 4C fluctuates by connecting to the same reference numerals in the figure, the fluctuation will also affect the output windings 4a and 4b as described above, but the control power supply 1
2. Due to the function of the saturable reactor 9, not only the output voltage of the output winding 4C but also the output voltages of the other output windings 4a and 4b can be stabilized.

Note that in this embodiment, the output winding 4C, which has the lowest voltage,
This output winding 4C is used to stabilize the output with high precision.
However, if the medium voltage is to be stabilized with high precision, the output of the output winding 4b is detected, and if the voltage is higher, the output of the output winding 4a is detected by the control power supply 12.
What is necessary is to detect it by .

Note that, for this reason, the stabilized state of the output voltage of the other output windings becomes somewhat unstable, but the output windings 4a, 4b, 4C, and controlled winding 10a are adjusted so that this instability is kept small.
, 10 b , 10 C, etc. are set.

Further, in the above embodiment, the resonance capacitor 5 is connected to the resonance winding 4, but the connection position of the resonance capacitor 5 is between each output winding 4a, 4b, 4.
The same effect can be obtained by causing parallel resonance with any one of the output windings of C as a representative.

As described above, according to this configuration, each output voltage of the ferro-resonant transformer having a large number of output terminals can be stabilized simultaneously with one saturable reactor.

As described above, the present invention detects output voltage fluctuations due to temperature rise of the ferro-resonant transformer, output voltage fluctuations due to load fluctuations, and output voltage fluctuations due to alternating current voltage frequency fluctuations from a single output voltage state. By changing the inductance of the controlled winding of the saturable reactor to an appropriate value, the stability of the output voltage of the multiple output terminals of the ferro-resonant transformer can be improved, and the number of components making up the circuit can be improved. It has the characteristics that the device is simple and there are few.

[Brief explanation of drawings]

Figure 1 is an example of a stabilizing circuit for a single-output ferro-resonant transformer, Figure 2 is an example of its saturable reactor, Figure 3 is an illustration of its operation, and Figure 4 is a circuit of an embodiment of the present invention. , FIG. 5 is an example of the saturable reactor. 2... Iron resonant transformer, 3... Input winding, 4... Resonant winding, 4 a , 4 b , 4
C...Output winding, 9...Saturable noactor, 10 a...First controlled winding, 10
b, 10C... Second controlled winding, 11...
... Control winding, 12... Control power supply.

Claims (1)

[Scope of utility model registration request] An iron-resonant transformer that includes an input winding wound around an iron core, a plurality of output windings, a resonant winding, and a resonant capacitor, a control winding wound around an iron core, a first controlled winding, one or more The resonant winding of the ferro-resonant transformer comprises a saturable reactor comprising a plurality of second controlled windings, and a control power source that detects the output voltage of one of the output windings and applies it to the control winding. The first controlled winding is connected in series in a resonant circuit of the inductance of the ferro-resonant transformer and the resonant capacitor. The inductance value of the first controlled winding is changed by connecting any of the wires in series and passing a control current through the control winding by the control power supply.
By making the voltage across the controlled winding variable and applying it to each voltage of the plurality of output windings of the ferro-resonant transformer according to the number of windings, it is possible to make the plurality of output voltages constant. Features: Ferro-resonant transformer voltage stabilization device.