JP6905452B2 - Transformer - Google Patents

Description

The present invention relates to a transformer device.

As an alternative to the traditional transformer using an iron core, a new "transformer device" that transforms only by an electric circuit has been proposed (see, for example, Patent Document 1). According to such a transformer device, it is possible to realize a dramatic reduction in size and weight.

JP 2015-80397

However, in a transformer device as described above, since the input end to the output end are configured only by an electric circuit, it is difficult to raise the insulation resistance between the input and output to a high level, and therefore, between the input and output. Leakage current that cannot be ignored flows. Therefore, reducing this leakage current is the next issue. Further, when trying to increase the transformation ratio in the above-mentioned transformer device, there is also a problem that the number of circuit components inevitably increases and the circuit scale becomes large.

In view of these problems, it is an object of the present invention to realize a large transformation ratio while suppressing the expansion of the circuit scale by reducing the leakage current between the input and output with respect to the transformer device that transforms only by the electric circuit. do.

The present disclosure includes the following inventions. However, the present invention is defined by the scope of claims.
This is a transformer provided between a low frequency power supply, which is the frequency of direct current or commercial alternating current, and a load, and each circuit has a plurality of switches, and by high frequency switching, with respect to the input. It is provided with a front-stage circuit and a rear-stage circuit that alternately invert the polarity of the output, and a transformer interposed between the output end of the front-stage circuit and the input end of the rear-stage circuit.
At least one of the first-stage circuit and the second-stage circuit is composed of a plurality of switches that are multiples of 2 connected in series to each other as a basic circuit configuration, and is an odd-th switch and an even number when viewed from either one end side of the series. The second switch is one end of the switch series, with the switch series that operates alternately on, the interconnection point of each switch in the switch series, and the end points of the switch series as a total of m nodes. When viewed in the order of 1 to m from the side, it is the first electric circuit as a collection destination of a plurality of electric circuits drawn from an odd number node, and one electric circuit drawn from an even number of nodes or as a collection destination of a plurality of electric circuits. The second electric circuit, the third electric circuit drawn from one end of the switch series, and the fourth electric circuit drawn from the other end, between the odd node and the first electric circuit, and from the even node. A reactorance element provided so as to exist at least one corresponding to at least (m-1) of the m nodes up to the second electric circuit is provided. One of the electric circuit pair of the first electric circuit and the second electric circuit and the electric circuit pair of the third electric circuit and the fourth electric circuit is an input, and the other is an output.

According to the transformer device of the present invention, in a transformer device that transforms with an electric circuit, it is possible to reduce the leakage current between the input and output and realize a large transformation ratio while suppressing the expansion of the circuit scale.

It is a circuit diagram which shows the transformer device which concerns on 1st example. FIG. 1A is a circuit diagram showing a state of actual connection when two switches on the upper side are on and two switches on the lower side are off among the four switches in FIG. 1. (B) is a circuit diagram in which the same circuit diagram as in (a) is rewritten in a stepped manner. FIG. 1A is a circuit diagram showing a state of actual connection when two switches on the lower side are on and two switches on the upper side are off among the four switches in FIG. 1. (B) is a circuit diagram in which the same circuit diagram as in (a) is rewritten in a stepped manner. The upper part is a waveform diagram showing the input voltage to the transformer, and the lower part is a waveform diagram showing the input current. It is a waveform diagram which shows voltage and current in the intermediate stage of a transformer, respectively. The upper part is a waveform diagram showing the output voltage (envelope) from the transformer, and the lower part is a waveform diagram showing the output current (envelope). It is a circuit diagram which shows the transformer device which concerns on 2nd example. The upper part is a waveform diagram showing the input voltage for the transformer device of the second example, and the lower part is a waveform diagram showing the input current. The upper part is a waveform diagram showing the output voltage (envelope) from the transformer, and the lower part is a waveform diagram showing the output current (envelope). It is a circuit diagram which shows the transformer device which concerns on 3rd example. It is a circuit diagram which shows the transformer device which concerns on 4th example. It is a transformer device slightly different from FIG. 1 for comparison with FIG. 13 described later. It is a circuit diagram which shows the transformer device which concerns on one Embodiment of this invention. FIG. 3 is a diagram in which a circuit for measuring impedance is connected to the transformer device of FIG. It is a circuit diagram which shows the transformer device which the position of a capacitor is different when paying attention to the pre-stage circuit of FIG. It is a circuit diagram which shows the transformer device which the position of the inductor is different when paying attention to the latter circuit of FIG. It is a circuit diagram which shows the transformer device which realizes the transformation ratio 32: 1 as an example of a high transformation ratio. It is a circuit diagram which shows the transformer device using the transformer with the midpoint tap. It is an equivalent circuit of FIG. It is a circuit diagram which shows the transformer device which used the transformer with the midpoint tap for both the primary side winding and the secondary side winding. It is a block diagram which shows the schematic structure of the transformer device as a whole. It is a figure which shows the basic form of the circuit which can be selected as a pre-stage circuit. It is a figure which shows the basic form of the circuit which can be selected as a post-stage circuit. It is a figure which shows the basic form of the circuit which can be selected as the post-stage circuit of a transformer device when the power source is a DC power source.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

(1) This is a transformer device provided between a low-frequency power supply having a DC or commercial AC frequency and a load, and each circuit has a plurality of switches, and by high-frequency switching, It includes a front-stage circuit and a rear-stage circuit that alternately invert the polarity of the output with respect to the input, and a transformer interposed between the output end of the front-stage circuit and the input end of the rear-stage circuit.
At least one of the first-stage circuit and the second-stage circuit is composed of a plurality of switches that are multiples of 2 connected in series to each other as a basic circuit configuration, and is an odd-th switch and an even number when viewed from either one end side of the series. The second switch is one end of the switch series, with the switch series that operates alternately on, the interconnection point of each switch in the switch series, and the end points of the switch series as a total of m nodes. When viewed in the order of 1 to m from the side, it is the first electric circuit as a collection destination of a plurality of electric circuits drawn from an odd number node, and one electric circuit drawn from an even number of nodes or as a collection destination of a plurality of electric circuits. The second electric circuit, the third electric circuit drawn from one end of the switch series, and the fourth electric circuit drawn from the other end, between the odd node and the first electric circuit, and from the even node. A reactorance element provided so as to exist at least one corresponding to at least (m-1) of the m nodes up to the second electric circuit is provided. One of the electric circuit pair of the first electric circuit and the second electric circuit and the electric circuit pair of the third electric circuit and the fourth electric circuit is an input, and the other is an output.

In the transformer device configured as described above, at least one of the front stage circuit and the rear stage circuit including the plurality of reactance elements can be transformed only by the electric circuit instead of the electromagnetic induction. Further, the transformer can maintain the electrical insulation between the primary and secondary and perform the transformation at a desired transformation ratio. Such a composite transformer makes it possible to realize a large transformer ratio while ensuring electrical insulation between the input and output.
In this way, in a transformer device that transforms with an electric circuit, it is possible to reduce the leakage current between the input and output and realize a large transformation ratio while suppressing the expansion of the circuit scale.

(2) Further, in the transformer device of (1), the secondary winding of the transformer has a midpoint tap, and one end and the other end of the secondary winding from the midpoint tap are the latter stages, respectively. It may be configured to be the reactance element in the circuit.
In this case, since the winding of the transformer also serves as the reactance element of the post-stage circuit, it is not necessary to separately provide the reactance element for the post-stage circuit.

(3) Further, in the transformer device of (1) or (2), the primary winding of the transformer has a midpoint tap, and from the midpoint tap to one end and the other end of the primary winding. May also be the reactance element in the pre-stage circuit.
In this case, since the winding of the transformer also serves as the reactance element of the pre-stage circuit, it is not necessary to separately provide the reactance element for the pre-stage circuit.

(4) Further, in any of the transformer devices (1) to (3), for example, the desired transformation ratio is insufficient in the combined value of the transformation ratios of the front-stage circuit and the rear-stage circuit. Can be realized by adjusting the transformation ratio of the transformer.
In this case, any desired transformation ratio can be achieved accurately. That is, even when it is difficult to accurately adjust the desired transformation ratio only with the front-stage circuit and the rear-stage circuit, the transformation ratio of the transformer can be arbitrarily set, so that any desired transformation ratio can be accurately realized. .. For example, in the case of step-down, the combined value of the transformation ratios of the front-stage circuit and the rear-stage circuit is (1 / even), but the desired transformation ratio for the entire transformer is (1 / odd). However, this can be achieved by setting the transformer transformation ratio.

[Details of Embodiment]
First, a configuration example of a transformer device by switching and a circuit configuration using a reactance element, which is a premise, will be described.

<< First example of premise >>
FIG. 1 is a circuit diagram showing a transformer device 1 according to the first example. In the figure, the transformer device 1 is provided between the AC power supply 2 and the load R (R is also a resistance value). The transformer device 1 includes a pair of capacitors C1 and C2, a pair of inductors L1 and L2, four switches S _r1 , S _r2 , S _b1 and S _b2 , and these switches S _r1 , S _r2 , S _b1 and S. _It includes a switching control unit 3 that controls on / off of b2. The switching frequency of the switching control unit 3 is, for example, 10 kHz or more.

The capacitance values of the pair of capacitors C1 and C2 may be the same value or may be different from each other. The same applies to the inductance values of the pair of inductors L1 and L2.
The transformer device 1 as shown in FIG. 1 includes two capacitors C1 and C2 as the front-stage circuit on the power supply side and two inductors L1 and L2 as the rear-stage circuit on the load side. It will be referred to.

The switches S _r1 , S _r2 , S _b1 , S _b2, and the switching control unit 3 constitute a switch device 4 for switching the circuit connection state of the transformer device 1. The switches S _r1 and S _r2 operate in synchronization with each other, and the switches S _b1 and S _b2 operate in synchronization with each other. Then, the pair of the switches S _r1 and S _{r2 and} the pair of the switches S _b1 and S _b2 operate so as to be exclusively and alternately turned on. The switches S _r1 , S _r2 , S _b1 , and S _b2 are semiconductor switching elements including, for example, a SiC element or a GaN element. A SiC element or a GaN element can switch at a higher speed than, for example, a Si element. Further, a sufficient withstand voltage (for example, 6 kV / one can be obtained) can be obtained without connecting the elements in multiple stages.

In FIG. 1, the power source is the AC power source 2. Since the switching frequency (10 kHz or more) is fast, the transformer device 1 can be applied to a commercial AC frequency (50 / 60 Hz), but of course, it can be applied even if the power supply is a direct current.
Further, since the switches S _r1 , S _r2 , S _b1 and S _b2 have built-in anti-parallel diodes in the case of FETs (Field Effect Transistors), for example, two such elements are connected in series in opposite directions to each other. To realize a bidirectional switch. When the input voltage Vin is a DC voltage, a one-way switch may be used.

In FIG. 1, the pair of capacitors C1 and C2 are connected in series with each other at the connection point M1. The AC power supply 2 is connected to both ends of the series. The series of the pair of capacitors C1, C2 are applied input voltage _{v in} flows input current _{i in} is.
Further, the pair of inductors L1 and L2 are connected in series with each other at the connection point M2. Then, the both ends of the series connection body, are applied input voltage v _m through the capacitors C1, C2 flows input current i _m. A current flows through the load R _{when either the switch S r2} or S _{b2 is on.} Here, the voltage applied to the load R is defined as v _out , and the output current flowing from the transformer device 1 to the load R is _defined as i out.

In FIG. 2A, of the four switches S _r1 , S _r2 , S _b1 and S _b2 in FIG. 1, the two switches S _r1 and S _r2 on the upper side are on and the two switches on the lower side are on. It is a circuit diagram which shows the state of the substance connection when S _b1 and S _{b2 are off.} The switch device 4 in FIG. 1 is not shown. Further, FIG. 2B is a circuit diagram in which the same circuit diagram as in FIG. 2A is rewritten in a stepped manner.
On the other hand, in FIG. 3A, of the four switches S _r1 , S _r2 , S _b1 and S _b2 in FIG. 1, the two switches S b1 and S b2 on the lower side _{are on and the switches S b1} and S _b2 on the upper side are on. It is a circuit diagram which shows the state of the physical connection when one switch S _r1 and S _{r2 is off.} Further, FIG. 3B is a circuit diagram in which the same circuit diagram as in FIG. 3A is rewritten in a stepped manner.

By alternately repeating the states of FIGS. 2 and 3, the voltage taken out through the connection point M1 of the series of capacitors C1 and C2 is further taken out through the connection point M2 of the series of inductors L1 and L2. It becomes the voltage to be. That is, the circuit configuration includes a front-stage circuit including a pair of capacitors C1 and C2 and a rear-stage circuit including a pair of inductors L1 and L2, and in each stage, the polarity of the output with respect to the input is inverted by switching. The current directions of the capacitors C1 and C2 are alternately reversed by switching, and the voltage directions of the inductors L1 and L2 are alternately reversed by switching.

In the transformer device 1 to the operation described above, under certain conditions, v _in ≒ 4v _out next without regard to (fluctuation of the value of R) load change, the output voltage, that is approximately 1/4 of the input voltage Has been confirmed (from Patent Document 1). Since there is no loss other than the load R, the output current is about 4 times the input current and the input impedance is 16 times the resistance value R.

The constant conditions, the inductance of the inductor L1, L2 L, the capacitance of the capacitor C1, C2 C, frequency _{f o} of the AC power source 2, as a circuit parameter condition when the switching frequency is _{f S,} with respect to the inductance, 2πf _o L << R << 2πf _s L. The capacitance is 1 / (2πf _s C) << R << 1 / (2πf _o C). By satisfying this circuit parameter condition, it is surely realized that the transformation ratio is constant with respect to the load fluctuation, and a more stable transformation operation with less distortion can be obtained. The difference indicated by the inequality sign preferably has a difference of, for example, one digit or more, more preferably two digits or more.

FIG. 4 is a waveform diagram showing the input voltage for the transformer device 1 on the upper side and the input current on the lower side.
Figure 5 is a waveform diagram showing the voltage v _m at the intermediate stage of the _transformer, the current i _m respectively. This is actually composed of a pulse train by switching, and has a waveform as shown in the figure as a whole.
Further, FIG. 6 is a waveform diagram showing the output voltage (envelope) from the transformer device 1 on the upper side and the output current (envelope line) on the lower side. As is clear from the comparison of FIGS. 4 and 6, the voltage is transformed into 1/4, and the current is quadrupled accordingly.

Here, when the configuration of the transformer device 1 of FIG. 1 is confirmed again, the transformer device 1 is a _{pre-stage circuit composed of switches S r1} , S _b1 and capacitors C1 and C2, and switches S _r2 , S _b2 and an inductor. It is provided with a post-stage circuit composed of L1 and L2. In the pre-stage circuit, the voltages applied to each of the plurality of capacitors C1 and C2 connected in series to each other and receiving the input voltage from the AC power supply 2 and the capacitors C1 and C2 are set to turn on / on the _{switches S r1} and S _b1. It is a circuit that outputs while alternating one target capacitor by turning it off and inverting the polarity. Similarly, the rear-stage circuits are connected in series with each other, and the voltages applied to the plurality of inductors L1 and L2 that receive the input voltage from the front-stage circuit and the inductors L1 and L2 are set to the switches S _r2 and S _b2. It is a circuit that outputs while alternating one target inductor and inverting the polarity by turning on / off.

In order to exert the transformer function as a transformer device, it is necessary that at least one of the front stage circuit and the rear stage circuit is a circuit as described above. However, there are other circuit variations (details will be described later).

<< Second example of premise >>
FIG. 7 is a circuit diagram showing the transformer device 1 according to the second example. The substance of the transformer device 1 is the same as that of FIG. 1, but the difference from FIG. 1 is that the AC power supply 2 and the load R are interchanged. In this case, the input / output is reversed, but the input voltage is boosted four times. With boosting, the output current becomes 1/4. The circuit parameter conditions are the same as in the first example.

FIG. 8 is a waveform diagram showing the input voltage for the transformer device 1 of the second example on the upper side and the input current on the lower side. Further, FIG. 9 is a waveform diagram showing the output voltage (envelope) from the transformer device 1 on the upper side and the output current (envelope line) on the lower side. As is clear from the contrast between FIGS. 8 and 9, the voltage is transformed four times, and the current is reduced to one quarter accordingly.
As described above, the transformer device 1 shown in FIG. 1 or FIG. 7 has input / output reversibility.

<< Third example of premise >>
FIG. 10 is a circuit diagram showing a transformer device 1 according to a third example. In this transformer device 1, the arrangement of the switches S _r1 , S _r2 , S _b1 and S _b2 is different from that in FIG. 1, but the other configurations are the same as those in FIG. That is, in FIG. 10, the switches S _b2 and S _r2 on the inductor L1 and L2 sides are upside down from those in FIG. Regarding the operation timing, as in the case of FIG. 1, the switches S _r1 and S _r2 operate in synchronization with each other, and the switches S _b1 and S _b2 operate in synchronization with each other. Then, the pair of the switches S _r1 and S _{r2 and} the pair of the switches S _b1 and S _b2 operate so as to be exclusively and alternately turned on. The circuit parameter conditions are the same as in the first example.

In the circuit of FIG. 10, the switches S _b2 and S _r2 on the inductor side perform switching operations in the opposite phase to the circuit of FIG.
According to such a switch arrangement and operation, the phase of the output with respect to the input can be inverted as compared with the case of FIG.

<< Premise 4th example >>
FIG. 11 is a circuit diagram showing a transformer device 1 according to a fourth example. In this transformer device 1, the pre-stage circuit is expanded in order to obtain a large transformation ratio. The basis of the pre-stage circuit is "16C" by forming an 8-stage configuration of "2C" similar to that in FIG. In this case, in addition to 16 switches (S _r1 , S _b1 , ..., S _r8 , S _b8 ), for example, 16 capacitors ((16 + 1) when a capacitor is required for insulation purposes) are required. It is known that such a pre-stage circuit outputs Vin / 16 with respect to the input voltage Vin. The subsequent circuit is the same as in FIG. 1, and has switches S _r9 and S _b9 and inductors L1 and L2. The subsequent circuit outputs Vin / 32 with respect to the input voltage Vin / 16.

《Transformer impedance》
FIG. 12 is a transformer device 1 slightly different from FIG. 1 for comparison with FIG. 13 described later. The difference from FIG. 1 is that the capacitor C3 is added to the front-stage circuit and the inductor L3 is added to the rear-stage circuit. Although the capacitor C3 and the inductor L3 are added in this way, since these elements do not contribute to the transformation, the transformer device 1 is also a type of "2C2L". The capacitor C3 is provided for the purpose of insulating against low frequencies, and the inductor L3 is provided for the purpose of insulating against high frequencies. For example, the capacitance was set to 4.7 μF for all C1, C2, and C3.

<< Embodiment with transformer >>
Next, FIG. 13 is a circuit diagram showing a transformer device 1 according to an embodiment of the present invention. In the figure, the transformer device 1 is provided between the AC power supply 2 and the load R (R is also a resistance value). A transformer 5 is provided between the front-stage circuit and the rear-stage circuit. That is, _{the output circuit pair of the pre-stage circuit by the switches S r1} and S _b1 and the capacitors C1 and C2 is connected to the primary winding of the transformer 5. The output voltage of the secondary winding of the transformer 5 is the input voltage to the subsequent circuit. Other circuit configurations and circuit details are the same as in FIG. For example, the number of turns of the transformer 5 is 1: 1 and the number of turns is 37.

《Impedance comparison》
FIG. 14 is a diagram in which a circuit for measuring impedance is connected to the transformer device 1 of FIG. That is, a sine wave voltage is applied from the AC power supply 6 (100 V, 50 Hz) between the input end and the output end of the transformer device 1, and the flowing current is measured by the current sensor 7 to obtain the impedance. The impedance is obtained in the same manner for the transformer device 1 (without a transformer) shown in FIG.

The result was about 300Ω in the case of the transformer device 1 (without a transformer) in FIG. 12, and about 20MΩ in the case of the transformer device 1 (with a transformer) in FIG. In this way, by inserting the transformer 5, the insulation performance between the input end and the output end of the transformer device 1 can be significantly improved. Further, by setting the insertion position of the transformer 5 between the front circuit and the rear circuit, the frequency of the voltage applied to the transformer 5 is a switching frequency, which is a high frequency (for example, 10 kHz or more). Therefore, the transformer used is a high-frequency transformer, and a compact and lightweight transformer can be used. Further, since the turns ratio can be set arbitrarily, it is possible to realize a large transformation ratio while suppressing an increase in the scale of the electric circuit.

Further, by using the transformer 5, for example, it is possible to realize a desired transformation ratio by adjusting the transformation ratio of the transformer, which is insufficient in the combined value of the transformation ratios of the front stage circuit and the rear stage circuit. can. In this case, any desired transformation ratio can be achieved accurately. That is, even when it is difficult to accurately adjust the desired transformation ratio only with the front-stage circuit and the rear-stage circuit, the transformation ratio of the transformer can be arbitrarily set, so that any desired transformation ratio can be accurately realized. .. For example, in the case of step-down, the combined transformation ratio of the front-stage circuit and the rear-stage circuit is (1 / even), but even when the desired transformation ratio of the entire transformer is (1 / odd). This can be achieved by setting the transformer transformation ratio. Specifically, for example, if the transformation ratio of the front-stage circuit is (1/2), the transformation ratio of the transformer 5 is (1 / 3.75), and the transformation ratio of the rear-stage circuit is (1/2), the whole is A transformation ratio of (1/15) is obtained.

<< Deformation example of the position of the reactance element >>
Here, variations in the insertion position of the capacitor in the pre-stage circuit will be described. FIG. 15 is a circuit diagram showing a transformer device 1 in which the positions of capacitors C1 and C2 are different when focusing on the pre-stage circuit 1f of FIG. _{When the entire switches S r1} and S _b1 connected in series with each other are viewed as a "switch series", one end of the switch series is node n11, the other end is node n13, and the interconnection point is node n12. In addition to FIG. 13, there are the following examples of how to provide the capacitor.

In FIG. 15, in the pre-stage circuit 1f of (a), the capacitor C1 is provided in the electric circuit connecting the node n12 and the primary winding of the transformer 5, and the capacitor C2 is provided between the node n13 and the connection point M1.
In the pre-stage circuit 1f of (b), the capacitor C1 is provided between the node n11 and the connection point M1, and the capacitor C2 is provided in the electric circuit connecting the node n12 and the primary winding of the transformer 5.
In the pre-stage circuit 1f of (c), the capacitor C1 is provided between the node n11 and the connection point M1, and the capacitor C2 is provided in the electric circuit connecting the connection point M1 and the primary winding of the transformer 5.
In the pre-stage circuit 1f of (d), the capacitor C1 is provided between the node n13 and the connection point M1, and the capacitor C2 is provided in the electric circuit connecting the connection point M1 and the primary winding of the transformer 5.

The procedure for providing the capacitors shown in FIGS. 13 and 15 can be expressed as follows.
That is, at least two capacitors are required in the pre-stage circuit, and at least one capacitor needs to be inserted between the nodes n11, n12, and n13. For example, in FIG. 13, there is a capacitor C1 between the nodes n11 and n12 via the primary winding of the transformer 5, a capacitor C2 between the nodes n12 and n13, and the nodes n11 and n13. There are capacitors C1 and C2 between them.

To give another example, in FIG. 15C, there are capacitors C1 and C2 between nodes n11 and n12, capacitors C2 between nodes n12 and n13, and nodes n11. There is a capacitor C1 between the n13 and the capacitor C1.

This law can be applied similarly even if the pre-stage circuit increases not only to "2C" but also to "4C" and "6C". Assuming that the multiple of "2C" is n (natural number), at least 2n capacitors are required in the pre-stage circuit, and at least one capacitor needs to be inserted between the respective nodes.

Next, variations in the insertion position of the inductor in the subsequent circuit will be described.
FIG. 16 is a circuit diagram showing a transformer device 1 in which the positions of the inductors L1 and L2 are different when focusing on the subsequent circuit 1r of FIG. _{When the entire switches S r2} and S _b2 connected in series with each other are viewed as a "switch series", one end of the switch series is node n21, the other end is node n23, and the interconnection point is node n22. In addition to FIG. 13, there are the following examples of how to provide the inductor.

In FIG. 16, in the subsequent circuit 1r of (a), the inductor L1 is provided in the electric circuit connecting the node n22 and the load, and the inductor L2 is provided between the node n23 and the connection point M2.
In the subsequent circuit 1r of (b), the inductor L1 is provided between the node n21 and the connection point M2, and the inductor L2 is provided in the electric circuit connecting the node n22 and the load.
In the subsequent circuit 1r of (c), the inductor L1 is provided between the node n21 and the connection point M2, and the inductor L2 is provided in the electric circuit connecting the connection point M2 and the load.
In the subsequent circuit 1r of (d), the inductor L1 is provided between the node n23 and the connection point M2, and the inductor L2 is provided in the electric circuit connecting the connection point M2 and the load.

The procedure for providing the inductors shown in FIGS. 13 and 16 can be expressed as follows.
That is, at least two inductors are required in the subsequent circuit, and at least one inductor needs to be inserted between the nodes n21, n22, and n23. For example, in FIG. 13, there is an inductor L1 between the nodes n21 and n22 via the load R, an inductor L2 between the nodes n22 and n23, and an inductor between the nodes n21 and n23. There are L1 and L2.

To give another example, in FIG. 16B, there are inductors L1 and L2 between nodes n21 and n22, inductors L2 between nodes n22 and n23, and node n21. There is an inductor L1 between and n23.

《Transformers with high transformation ratio》
FIG. 17 is a circuit diagram showing a transformer device 1 that realizes a transformation ratio of 32: 1 as an example of a high transformation ratio. Assuming that a transformer is not used, the transformer device 1 that realizes a transformation ratio of 32: 1 has, for example, a “16C2L” configuration in which the front-stage circuit has eight stages, as shown in FIG. In this case, the number of circuit elements increases. However, as shown in FIG. 17, if a transformer 5 having a transformation ratio of 8: 1 is interposed in the middle, both the front-stage circuit and the rear-stage circuit may have the simplest one-stage (2C2L) configuration. That is, in the case of step-down, the input voltage Vin may be stepped down to (Vin / 2) in the pre-stage circuit, stepped down to (Vin / 16) in the transformer, and finally output (Vin / 32) in the post-stage circuit. can.

In such a transformer device 1, for example, in the case of a circuit having an AC input of several hundred V and a power of about 1 kW, the volume of one stage of the front stage circuit and the rear stage circuit is ^{about 500 cm 3} and the isolation transformer is about ^{200 cm 3.} .. In this case, the volume of the transformerless transformer 1 of FIG. 11 is 500 × 8 + 500 × 1 + 200 × 0 = 4500 cm ³ , and the volume of the transformerless transformer 1 of FIG. 17 is 500 × 1 + 500 × 1 + 200 × 1 = 1200 cm ³ . That is, the volume of the transformer-equipped transformer 1 in FIG. 17 is about 27% of the volume of the transformer-less transformer 1 in FIG. 11, and compactification can be realized.

<< Utilization of midpoint tap transformer >>
FIG. 18 is a circuit diagram showing a transformer device 1 using a transformer 5 with a midpoint tap. For example, as is clear from comparison with FIG. 13, the inductor that should exist as a post-stage circuit is substituted (combined) with the winding of the transformer 5 with a midpoint tap in the transformer device 1 of FIG. In FIG. 18, a _{switch series body formed by connecting a pair of switches S r2} and S _b2 in series with each other is connected to both ends of the secondary winding of the transformer 5. The load R is connected between the midpoint tap of the secondary winding and the node n22, which is the interconnection point of the switch series.

FIG. 19 is an equivalent circuit of FIG. That is, the secondary winding of the transformer 5 can be considered, for example, the inductor L1 from the midpoint tap to one end and the inductor L2 from the midpoint tap to the other end. The midpoint tap is the connection point M2 of the two inductors L1 and L2. Considering this way, the latter-stage circuit of FIG. 19 is similar to the latter-stage circuit of FIG. Therefore, the transformer 5 can perform transformation at its own turns ratio, while the subsequent circuit including the inductors L1 and L2 can perform half transformation (step-down).

By arbitrarily designing the turns ratio of the transformer 5, the transformation ratio of the transformer device 1 as a whole can be arbitrarily designed. For example, if you want to set the transformation ratio of the entire circuit to 4: 1, it can be realized by setting the turns ratio of the transformation ratio to 1: 1. If you want to set the transformation ratio of the entire circuit to 8: 1, the transformation ratio of This can be achieved by setting the turns ratio to 2: 1. That is, the step-down can be performed with a transformation ratio of the front circuit 2: 1, the transformer 2: 1, and the rear circuit 2: 1.

In the case of FIGS. 18 and 19, since both inductors in the subsequent circuit are not required, the volume and weight can be significantly reduced. For example hundreds .mu.H, the 10A about the inductor volume and weight, respectively one per about 100 cm ^3, a 0.3～0.5Kg. In this case, by reducing the inductor, the volume can be reduced by about 20% and the weight can be reduced by about 30%.

FIG. 20 is a circuit diagram showing a transformer device 1 using a transformer 5 with a midpoint tap for both the primary winding and the secondary winding. In this case, the front-stage circuit has the same configuration as the rear-stage circuit.
In this case, as compared with FIG. 18, since the two capacitors in the pre-stage circuit are not required, the volume can be further reduced. For example several hundred V withstand voltage, because the volume of the capacitor having μF is about 20~50cm per ^3, volume can be expected reduction of about 10%. In such a transformer device 1, the transformation ratio as a whole can be arbitrarily designed by arbitrarily designing the turns ratio of the transformer 5. For example, if the transformation ratio of the entire circuit is to be 4: 1, it can be realized by setting the turns ratio of the transformation ratio to 4: 1, and if the transformation ratio of the entire circuit is to be 8: 1, the transformation ratio is This can be achieved by setting the turns ratio to 8: 1.

<< Variations of front-stage circuit and rear-stage circuit >>
Since there are various variations in the front-stage circuit and the rear-stage circuit, a supplementary explanation will be given below.
FIG. 21 is a block diagram showing a schematic configuration of the transformer device 1 as a whole. That is, the transformer device 1 is provided between the power supply 2 and the load R, and has input ports P1 and P2 on the front end side connected to the power supply 2, and output ports P3 and P4 on the rear end side. It is provided with 1f and a rear-stage circuit 1r having output ports P7 and P8 on the rear end side connected to the load R and input ports P5 and P6 on the front end side. A transformer 5 is interposed between the front circuit 1f and the rear circuit 1r.

FIG. 22 is a diagram showing a basic form of a circuit that can be selected as the pre-stage circuit 1f.
As the pre-stage circuit of the transformer device 1, any of the following (F1) to (F5) can be selected. However, what is shown here is the basic type, and there is also an applied type regarding the position on the electric circuit where the reactance element (capacitor, inductor) is provided (for example, FIG. 15).

(F1) is the pre-stage circuit 1f shown in FIG. 22 (a).
That is, in (F1), both ends of a series formed by connecting a pair of capacitors in series at a capacitor connection point are connected to input port P1 and input port P2, respectively, and the capacitor connection point is connected to output port P4. This is a pre-stage circuit in which the first switch between the input port P1 and the output port P3 and the second switch between the input port P2 and the output port P3 are alternately turned on by switching.

(F2) is a pre-stage circuit in which the pre-stage circuit 1f shown in FIG. 22 (b) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, a capacitor is also required for the line directly connected to the output port P3.
That is, (F2) is a unit in which a capacitor is inserted in the line directly connected to the output port P3 in the pre-stage circuit of (F1), and the input ports P1 and P2 of a plurality of units are connected in series to each other to form a plurality of units. This is a pre-stage circuit in which the output ports P3 and P4 of the above are connected in parallel with each other.

(F3) is the pre-stage circuit 1f shown in FIG. 22 (c).
That is, in (F3), both ends of a series formed by connecting a pair of inductors in series at the inductor connection points are connected to the output port P3 and the output port P4, respectively, and the inductor connection points are connected to the input port P2. This is a pre-stage circuit in which the first switch between the input port P1 and the output port P3 and the second switch between the input port P1 and the output port P4 are alternately turned on by switching.

(F4) is a pre-stage circuit in which the pre-stage circuit 1f shown in FIG. 22 (d) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, an inductor is also required for the line directly connected to the input port P1.
That is, in the pre-stage circuit of (F3), the input ports P1 and P2 of a plurality of units are connected in series to each other, and the output ports of the plurality of units are connected to each other, with the line directly connected to the input port P1 having an inductor inserted as one unit. This is a pre-stage circuit in which P3 and P4 are connected in parallel with each other.

(F5) is the pre-stage circuit 1f shown in FIG. 22 (e).
That is, (F5) is a pre-stage circuit of a full bridge circuit composed of four switches, input from input ports P1 and P2 and output from output ports P3 and P4.

FIG. 23 is a diagram showing a basic form of a circuit that can be selected as the subsequent circuit 1r. However, what is shown here is the basic type, and there is also an applied type regarding the position on the electric circuit where the reactance element (capacitor, inductor) is provided (for example, FIG. 16).
As the subsequent circuit of the transformer device 1, any of the following (R1) to (R5) can be selected.

(R1) is the subsequent circuit 1r shown in FIG. 23 (a).
That is, in (R1), both ends of a series formed by connecting a pair of inductors in series at the inductor connection points are connected to the input port P5 and the input port P6, respectively, and the inductor connection points are connected to the output port P8. This is a post-stage circuit in which the first switch between the input port P5 and the output port P7 and the second switch between the input port P6 and the output port P7 are alternately turned on by switching.

(R2) is a post-stage circuit in which the post-stage circuit 1r shown in FIG. 23 (b) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, an inductor is also required for the line directly connected to the output port P7.
That is, in (R2), the input ports P5 and P6 of a plurality of units are connected in series with each other, with the line directly connected to the output port P7 in the subsequent circuit of (R1) having an inductor inserted as one unit, and a plurality of units are connected. This is a post-stage circuit in which the output ports P7 and P8 of the above are connected in parallel with each other.

(R3) is the subsequent circuit 1r shown in FIG. 23 (c).
That is, in (R3), both ends of a series formed by connecting a pair of capacitors in series at a capacitor connection point are connected to an output port P7 and an output port P8, respectively, and the capacitor connection points are connected to an input port P6. This is a post-stage circuit in which the first switch between the input port P5 and the output port P7 and the second switch between the input port P5 and the output port P8 are alternately turned on by switching.

(R4) is a post-stage circuit in which the post-stage circuit 1r shown in FIG. 23 (d) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, a capacitor is also required for the line directly connected to the input port P5.
That is, (R4) is a unit in which a capacitor is inserted in the line directly connected to the input port P5 in the subsequent circuit of (R3), and the input ports P5 and P6 of a plurality of units are connected in series to each other to form a plurality of units. This is a post-stage circuit in which the output ports P7 and P8 of the above are connected in parallel with each other.

(R5) is the subsequent circuit 1r shown in FIG. 23 (e).
That is, (R5) is a post-stage circuit of a full bridge circuit composed of four switches, input from input ports P5 and P6, and output from output ports P7 and P8.

Then, it is configured to include any one of the above-mentioned front stage circuits (F1) to (F5) and any one of the rear stage circuits (R1) to (R5), and the front stage circuit is (F5). ), The combination that the subsequent circuit is (R5) may be excluded as long as it is a transformer device.

As described above, various transformation ratios can be easily realized.
Further, a plurality of sets of transformer devices including any of the above-mentioned front-stage circuits and rear-stage circuits may be configured in a longitudinal manner. In this case, a large transformation ratio can be realized for both step-down and step-up.
In each of the above embodiments, the power source is an AC power source 2, but each of the above-mentioned transformer devices 1 can also be applied to a DC power source and can also be used as a DC / DC converter.

<< Variation of the post-stage circuit in the case of DC power supply >>
When the power source is a DC power source, any of the following (R1) to (R5) can be selected as the subsequent circuit of the transformer device 1. The diode is a kind of switch. That is, if a voltage is applied in the forward direction, it becomes conductive (on), and if a voltage is applied in the reverse direction, it becomes non-conducting (off).

(R1) is the subsequent circuit 1r shown in FIG. 24 (a).
That is, in (R1), both ends of a series formed by connecting a pair of inductors in series at the inductor connection points are connected to the input port P5 and the input port P6, respectively, and the inductor connection points are connected to the output port P8. In the subsequent circuit, the first diode between the input port P5 and the output port P7 and the second diode between the input port P6 and the output port P7 are alternately conducted according to the polarity of the input voltage. be.

(R2) is a post-stage circuit in which the post-stage circuit 1r shown in FIG. 24 (b) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, an inductor is also required for the line directly connected to the output port P7.
That is, in (R2), the input ports P5 and P6 of a plurality of units are connected in series with each other, with the line directly connected to the output port P7 in the subsequent circuit of (R1) having an inductor inserted as one unit, and a plurality of units are connected. This is a post-stage circuit in which the output ports P7 and P8 of the above are connected in parallel with each other.

(R3) is the subsequent circuit 1r shown in FIG. 24 (c).
That is, in (R3), both ends of a series formed by connecting a pair of capacitors in series at a capacitor connection point are connected to an output port P7 and an output port P8, respectively, and the capacitor connection point is connected to an input port P6. In the subsequent circuit, the first capacitor between the input port P5 and the output port P7 and the second capacitor between the input port P5 and the output port P8 are alternately conducted according to the polarity of the input voltage. be.

(R4) is a post-stage circuit in which the post-stage circuit 1r shown in FIG. 24 (d) is regarded as one unit and is multi-staged with a plurality of units. In order to increase the number of stages, a capacitor is also required for the line directly connected to the input port P5.
That is, (R4) is a unit in which a capacitor is inserted in the line directly connected to the input port P5 in the subsequent circuit of (R3), and the input ports P5 and P6 of a plurality of units are connected in series to each other to form a plurality of units. This is a post-stage circuit in which the output ports P7 and P8 of the above are connected in parallel with each other.

(R5) is the subsequent circuit 1r shown in FIG. 24 (e).
That is, (R5) is a post-stage circuit of a full bridge circuit composed of four diodes, input from input ports P5 and P6, and output from output ports P7 and P8.

The directions of the diodes in FIGS. 24 (a) to 24 (d) may be opposite to those shown in the drawings (the anode and cathode are opposite).

As described above, when the power supply is a DC power supply, there are many circuit variations in the subsequent stage. First, as in the case of the AC power supply, any one of the front stage circuits (F1) to (F5) in FIG. 22 A transformer that is configured to include any one of the latter-stage circuits (R1) to (R5) in FIG. 23 and excludes a combination in which the first-stage circuit is (F5) and the second-stage circuit is (R5). It may be a device.
Further, it is configured to include any one of the front-stage circuits (F1) to (F5) of FIG. 22 and any one of the rear-stage circuits (R1) to (R5) of FIG. 24, and the front stage. A transformer device that excludes the combination of the circuit being (F5) and the subsequent circuit being (R5) may be used.

"summary"
In summary, the transformer device disclosed as the embodiment of the present specification is a transformer device provided between a low-frequency power source having a frequency of direct current or commercial alternating current and a load. This transformer device includes a front-stage circuit and a rear-stage circuit, and a transformer is interposed between the output end of the front-stage circuit and the input end of the rear-stage circuit. The front-stage circuit and the rear-stage circuit each have a plurality of switches, and the polarity of the output is alternately inverted with respect to the input by high-frequency switching.

At least one of the front-stage circuit and the rear-stage circuit is formed by connecting a plurality of switches that are multiples of 2 in series with each other, and the odd-numbered switch and the even-numbered switch when viewed from one end side of the series body are It is equipped with a series of switches that operate alternately on.

Further, when the interconnection points of the switches in the switch series and the points at both ends of the switch series are regarded as a total of m nodes and viewed in the order of 1 to m from any one end side of the switch series, they are pulled out from the odd nodes. The first electric circuit as the aggregation destination of a plurality of electric circuits, the second electric circuit which is one electric circuit drawn from even-numbered nodes, or the second electric circuit as the aggregation destination of a plurality of electric circuits, and the third electric circuit drawn from one end of the switch series. There is an electric circuit and a fourth electric circuit drawn from the other end.

At least one reactance element corresponds to at least (m-1) of m nodes between the odd-numbered nodes and the first electric circuit and between the even-numbered nodes and the second electric circuit. It is provided to exist. Then, either one of the electric circuit pair of the first electric wire and the second electric wire and the electric circuit pair of the third electric wire and the fourth electric wire becomes an input, and the other becomes an output.

Applying the general description of the electric circuit and the like to FIG. 13, for example, in the front circuit, the interconnection point (n12) of each switch in the _{switch series (S r1} , S _{b1) and both ends of the switch series} When the points (n11, n13) are regarded as a total of m (3 in this case) nodes and viewed in the order of 1 to m (1 to 3) from any one end side of the switch series, the odd nodes (n11, n13) ) As a collection destination of a plurality of electric circuits (the electric circuit from the connection point M1 to the primary winding of the transformer 5), and one electric circuit drawn from the even node (n12) or a plurality of electric circuits. The second electric circuit (the electric circuit from the node n12 to the primary winding of the transformer 5) and the third electric circuit (the electric circuit from the node n11 to the AC power source 2) drawn from one end of the switch series, There is also a fourth electric circuit (electric circuit from the node n13 to the AC power supply 2) drawn from the other end.

The reactance elements (capacitors C1 and C2) are at least (m-1) out of m nodes between the odd-numbered nodes and the first electric circuit and between the even-numbered nodes and the second electric circuit (m-1). Here, there is at least one corresponding to two) nodes (n11, n13). Then, one of the electric circuit pair of the first electric wire and the second electric wire and the electric circuit pair of the third electric wire and the fourth electric wire (here, the latter) is an input, and the other (here, the former) is an output.

On the other hand, in the subsequent circuit of FIG. 13, _{the interconnection points (n22) of each switch in the switch series (S r2} , S _b2 ) and the end points (n21, n23) of the switch series are a total of m (3 in this case). When viewed in the order of 1 to m (1 to 3) from any one end side of the switch series, the first as a collection destination of a plurality of electric circuits drawn from odd nodes (n21, n23). An electric circuit (electric circuit from the connection point M2 to the load R) and a second electric circuit (electric circuit from the node n22 to the load R) which is one electric circuit drawn from an even number of nodes (n22) or is a collection destination of a plurality of electric circuits. ), A third electric circuit drawn from one end of the switch series (electric circuit from the node n21 to the secondary winding of the transformer 5), and a fourth electric circuit drawn from the other end (secondary winding of the transformer 5 from the node n23). There is an electric circuit to the line).

The reactance elements (inductors L1 and L2) are at least (m-1) out of m nodes between the odd-numbered nodes and the first electric circuit and between the even-numbered nodes and the second electric circuit (m-1). Here, there is at least one corresponding to two) nodes (n21, n23). Then, one of the electric circuit pair of the first electric wire and the second electric wire and the electric circuit pair of the third electric wire and the fourth electric wire (here, the latter) is an input, and the other (here, the former) is an output.

The same relationship applies to other circuit variations.

In a transformer device having such a circuit configuration, at least one of a front-stage circuit and a rear-stage circuit including a plurality of reactance elements can be transformed only by an electric circuit instead of electromagnetic induction. Further, the transformer can maintain the electrical insulation between the primary and secondary and perform the transformation at a desired transformation ratio. Such a composite transformer makes it possible to realize a large transformer ratio while ensuring electrical insulation between the input and output.

<< Supplement >>
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 Transformer 1f Front circuit 1r Rear circuit 2 AC power supply, power supply 3 Switching control unit 4 Switch device 5 Transformer 6 AC power supply 7 Current sensor C1 to C3 Capacitor L1 to L3 Inductor S _{b1 to} S _b9 Switch S _{r1 to} S _r9 Switch M1 , M2 Connection points n11, n12, n13, n21, n22, n23 Nodes P1 to P8 Port R Load

Claims (4)

A low frequency power with a frequency of the commercial AC, a transformer for an AC provided between the load,
Each circuit has a plurality of switches, and the polarity of the output is alternately inverted with respect to the input by high-frequency switching.
A transformer interposed between the output end of the front-stage circuit and the input end of the rear-stage circuit is provided.
The preceding circuit and the subsequent circuits has a basic circuit configuration,
A switch series that consists of multiple switches that are multiples of 2 connected in series to each other, and the odd-numbered switch and even-numbered switch are turned on alternately when viewed from one end of the series.
When the interconnection points of the switches in the switch series body and the end points of the switch series body are regarded as a total of m nodes, and viewed in order from one end side of any one end side of the switch series body, from an odd number node. A first electric circuit as a collection destination of a plurality of electric lines to be drawn out, and a second electric line as a collection destination of one electric line or a plurality of electric lines drawn out from even-numbered nodes.
A third electric circuit drawn from one end of the switch series and a fourth electric circuit drawn from the other end.
Between the odd-numbered nodes and the first electric circuit, and between the even-numbered nodes and the second electric circuit, at least one of the m nodes corresponds to at least (m-1) nodes, respectively. It is equipped with a reactance element that is provided so that it exists individually.
A transformer device in which either one of the first electric circuit and the second electric circuit pair and the third electric circuit and the fourth electric circuit pair is an input and the other is an output. The first aspect of claim 1, wherein the secondary winding of the transformer has a midpoint tap, and one end and the other end of the secondary winding are also reactance elements in the subsequent circuit, respectively. Transformer. Claim 1 or claim, wherein the primary winding of the transformer has a midpoint tap, and from the midpoint tap to one end and the other end of the primary winding are also the reactance elements in the pre-stage circuit, respectively. Item 2. The transformer device according to item 2. Any of claims 1 to 3 which realizes a desired transformer ratio by adjusting the transformer ratio for which the combined value of the transformer ratios of the front-stage circuit and the rear-stage circuit is insufficient with the transformer ratio of the transformer. The transformer device according to item 1.

Images