JP2019088127A - Potential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a large transformation ratio while reducing a leakage current between input / output and suppressing an expansion of a circuit scale in a transformer device for transforming with an electric circuit. SOLUTION: This is a transformer device 1 provided between a low frequency power supply 2 having a frequency of direct current or commercial alternating current and a load R, and each circuit has a plurality of switches Sr1, Sr2, Sb1 and Sb2. A transformer 5 interposed between the output end of the front stage circuit and the input end of the rear stage circuit, and the front stage circuit and the rear stage circuit, which have and alternately invert the polarity of the output with respect to the input by high frequency switching. I have. At least one of the front-stage circuit and the rear-stage circuit is transformed by an electric circuit. [Selection diagram] FIG. 13

Description

  The present invention relates to a transformer device.

  As an alternative to the traditional transformer using a core, a new "transforming device" has been proposed which performs transformation only with an electric circuit (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, A

  However, in the above-described transformer device, since the input end to the output end are constituted only by the electric circuit, it is difficult to make the insulation resistance between the input and output high level, and therefore, between the input and output A non-negligible leakage current flows. Therefore, reducing the leakage current is the next issue. In addition, when attempting to increase the transformation ratio in the above-described transformation device, there is also a problem that the circuit components inevitably increase and the circuit scale becomes large.

  In view of such problems, the object of the present invention is to reduce leakage current between input and output and realize a large transformation ratio while suppressing expansion of the circuit scale, with respect to a transformer that performs transformation only with an electric circuit. Do.

The present invention is a transformer device provided between a low frequency power source having a frequency of direct current or commercial alternating current and a load, each circuit having a plurality of switches, and switching at high frequency by switching at high frequency. A front circuit and a rear circuit, which alternately invert the polarity of the output, and a transformer interposed between an output end of the front circuit and an input terminal of the rear circuit, are provided.
As a basic circuit configuration, at least one of the pre-stage circuit and the post-stage circuit is configured by connecting a plurality of switches that are multiples of 2 in series with one another. The switch series body alternately turning on with the second switch, the connection point between the switches in the switch series body, and the two end points of the switch series body as a total of m nodes, any one end of the switch series body When viewed from the side in the order of 1 to m, a first electric path as a collection destination of a plurality of electric paths drawn from an odd node and one electric path drawn from an even node or a collection destination of a plurality of electric paths A second electric path, a third electric path drawn from one end of the switch series body, a fourth electric path drawn from the other end, and the first electric And at least one of the m nodes corresponding to at least (m-1) nodes between the even numbered node and the second electric path. The first electric path and the electric path pair of the second electric path, and one of the third electric path and the electric path pair of the fourth electric path is an input, and the other is an output.

  According to the transformer device of the present invention, in a transformer device that performs transformation with an electric circuit, leakage current between input and output is reduced, and a large transformation ratio can be realized while suppressing expansion of the circuit scale.

It is a circuit diagram showing a transformer device concerning the 1st example. (A) is a circuit diagram showing a state of entity connection when two upper switches among the four switches in FIG. 1 are on and two lower switches are off. (B) is a circuit diagram in which the same circuit diagram as (a) is rewritten in a step shape. (A) is a circuit diagram showing a state of entity connection when two lower switches among four switches in FIG. 1 are on and two upper switches are off. (B) is a circuit diagram in which the same circuit diagram as (a) is rewritten in a step shape. The top is a waveform diagram representing the input voltage to the transformer, and the bottom is an input current. It is a wave form diagram showing the voltage in the middle stage of transformation, and current, respectively. The upper part is a waveform diagram representing the (envelope) of the output voltage from the transformer, and the lower is a (envelope) of the output current. It is a circuit diagram showing a transformer device concerning the 2nd example. The upper part is a waveform diagram showing the input voltage to the transformer device of the second example, and the lower part is an input current. The upper part is a waveform diagram representing the (envelope) of the output voltage from the transformer, and the lower is a (envelope) of the output current. It is a circuit diagram showing a transformer device concerning the 3rd example. It is a circuit diagram showing a transformer device concerning the 4th example. It is a transformer device slightly different from FIG. 1 for comparison with FIG. 13 mentioned later. It is a circuit diagram showing a transformer device concerning one embodiment of the present invention. It is a figure which connected the circuit which measures an impedance to the transformation apparatus of FIG. FIG. 14 is a circuit diagram showing a transformer device in which positions of capacitors are different in the case of focusing on the pre-stage circuit of FIG. FIG. 14 is a circuit diagram showing a transformer device in which positions of inductors are different in a case where attention is paid to a post-stage circuit of FIG. 13. It is a circuit diagram showing a transformation device which realizes transformation ratio 32: 1 as an example of high transformation ratio. It is a circuit diagram showing a transformer apparatus using a transformer with a midpoint tap. It is an equivalent circuit of FIG. It is a circuit diagram showing a transformer device using a transformer with a center point tap for both primary side winding and secondary side winding. It is a block diagram which shows the schematic structure which looked at the transformer device globally. It is a figure which shows the basic form of the circuit which can be selected as a front | former stage circuit. It is a figure which shows the basic form of the circuit which can be selected as a back | latter stage circuit. It is a figure which shows the basic form of the circuit which can be selected as a back | latter stage circuit of a transformation | transformation apparatus, when power supply is DC power supply.

[Summary of the embodiment]
The subject matter of the embodiments of the present invention includes at least the following.

(1) This is a transformer device provided between a low frequency power supply having a frequency of direct current or commercial alternating current and a load, and each circuit has a plurality of switches and is switched by high frequency switching, It has a front stage circuit and a rear stage circuit that alternately inverts 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.
As a basic circuit configuration, at least one of the pre-stage circuit and the post-stage circuit is configured by connecting a plurality of switches that are multiples of 2 in series with one another. The switch series body alternately turning on with the second switch, the connection point between the switches in the switch series body, and the two end points of the switch series body as a total of m nodes, any one end of the switch series body When viewed from the side in the order of 1 to m, a first electric path as a collection destination of a plurality of electric paths drawn from an odd node and one electric path drawn from an even node or a collection destination of a plurality of electric paths A second electric path, a third electric path drawn from one end of the switch series body, a fourth electric path drawn from the other end, and the first electric And at least one of the m nodes corresponding to at least (m-1) nodes between the even numbered node and the second electric path. The first electric path and the electric path pair of the second electric path, and one of the third electric path and the electric path pair of the fourth electric path is an input, and the other is an output.

In the transformer device configured as described above, at least one of the pre-stage circuit and the post-stage circuit including the plurality of reactance elements can perform the transformation only by the electric circuit instead of the electromagnetic induction. Also, the transformer can maintain electrical insulation between the primary and secondary and can perform transformation at a desired transformation ratio. By such complex transformation, a large transformation ratio can be realized while securing the electrical insulation between the input and the output.
Thus, in a transformer device that performs transformation with an electric circuit, leakage current between input and output is reduced, and a large transformation ratio can be realized while suppressing expansion of the circuit scale.

(2) Further, in the transformer device of (1), the secondary winding of the transformer has a center point tap, and from the middle point tap to one end and the other end of the secondary side winding are respectively the rear stage It may be configured that it is also the reactance element in the circuit.
In this case, since the winding of the transformer also serves as a reactance element of the subsequent stage circuit, it is not necessary to separately provide a reactance element for the subsequent stage circuit.

(3) Also, 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 be the reactance elements in the pre-stage circuit, respectively.
In this case, since the winding of the transformer also serves as a reactance element of the front stage circuit, it is not necessary to separately provide a reactance element for the front stage circuit.

(4) Further, in the transformer device according to any one of (1) to (3), for example, a transformer ratio of a portion lacking a desired transformer ratio by a combined value of each transformer ratio of the former circuit and the latter circuit. Can be adjusted by the transformation ratio of the transformer.
In this case, any desired transformation ratio can be accurately realized. That is, even if it is difficult to accurately adjust to the desired transformation ratio only with the front stage circuit and the rear stage circuit, the transformation ratio of the transformer can be set arbitrarily, so that the desired arbitrary transformation ratio can be realized accurately. . For example, in the case of step-down, the combined value of the transformation ratio of the front stage circuit and the rear stage circuit is (1 / even) transformation ratio, but the desired transformation ratio of the entire transformation device is (1 / odd) However, this can be realized by setting the transformation ratio of the transformer.

Details of Embodiment
First, a configuration example of a transformer device based on a circuit configuration using a reactance element and switching will be described.

«First example of premise»
FIG. 1 is a circuit diagram showing a transformer device 1 according to a first example. In the figure, the transformer device 1 is provided between an AC power supply 2 and a 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 and a switching control unit 3 for controlling on / off of the switch _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 different values. The same applies to the inductance values of the pair of inductors L1 and L2.
Since the transformer device 1 as shown in FIG. 1 includes two capacitors C1 and C2 as a front stage circuit on the power supply side and two inductors L1 and L2 as a rear stage circuit on the load side, the transformer device "2C2L" I will call it.

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. The pair of switches S _r1 and S _{r2 and} the pair of switches S _b1 and S _b2 operate so as to be alternately turned on alternately. The switches S _r1 , S _r2 , S _b1 and S _b2 are, for example, semiconductor switching elements formed of SiC elements or GaN elements. SiC devices or GaN devices can perform faster switching than, for example, Si devices. In addition, even without connecting the elements in multiple stages, a sufficient withstand voltage (for example, 6 kV / one is possible) can be obtained.

In FIG. 1, the power source is an AC power source 2. Since the switching frequency (10 kHz or more) is fast, the transformer device 1 is applicable to the frequency of commercial alternating current (50/60 Hz), but it is naturally applicable even if the power supply is direct current.
In addition, since the switches S _r1 , S _r2 , S _b1 , and S _b2 incorporate, for example, antiparallel diodes in the case of FETs (Field Effect Transistors), two such elements are connected in series in mutually opposite directions. To realize a bidirectional switch. When the input voltage Vin is a DC voltage, a unidirectional switch may be used.

In FIG. 1, a pair of capacitors C1 and C2 are connected in series with each other at a connection point M1. And the alternating current power supply 2 is connected to the both ends of the series body. An input voltage v _in is applied to a series body of a pair of capacitors C 1 and C 2, and an input current i _in flows.
Further, the pair of inductors L1 and L2 are connected in series to 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 in the load R when one of the switches S _r2 and S _b2 is on. Here, the voltage applied to the load R is v _out , and the output current flowing from the transformer device 1 to the load R is i _out .

Of (a) is 2, of the four switches _{S r1, S r2, S b1} , S b2 in FIG. 1, the two on the upper switch _{S r1, S r2} is on, two switches on the underside FIG. 7 is a circuit diagram showing a state of entity connection when S _b1 and S _b2 are off. The switch device 4 in FIG. 1 is not shown. Also, FIG. 2B is a circuit diagram in which the same circuit diagram as FIG.
On the other hand, FIG. 3A shows that the two switches S _b1 and S _b2 on the lower side among the four switches S _r1 , S _r2 , S _b1 and S _b2 in FIG. It is a circuit diagram showing a state of entity connection when one of the switches S _r1 and S _r2 is off. Also, FIG. 3B is a circuit diagram in which the same circuit diagram as FIG.

  By alternately repeating the states of FIG. 2 and FIG. 3, the voltage taken out via the connection point M1 of the series body of the capacitors C1 and C2 is further taken out via the connection point M2 of the series body of the inductors L1 and L2. Voltage. 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 direction of the current is alternately inverted due to switching for capacitors C1 and C2, and the direction of voltage is alternately inverted due to switching for inductors L1 and L2.

In the transformer device 1 operating as described above, v _in 4 4 v _out under constant conditions regardless of the load fluctuation (fluctuation of the value of R), and the output voltage becomes 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 condition is a circuit parameter condition in which the inductance of the inductors L1 and L2 is L, the capacitance of the capacitors C1 and C2 is C, the frequency of the AC power supply 2 is f _o , and the switching frequency is f _S. 2πf _o L << R << 2πf _s L. As for the capacitance, 1 / (2πf _s C) << R << 1 / (2πf _o C). By satisfying this circuit parameter condition, it is possible to ensure that the transformation ratio is constant with respect to load fluctuation, and to obtain a more stable transformation operation with less distortion. The difference indicated by the inequality sign is preferably, for example, a difference of one digit or more, more preferably two digits or more.

FIG. 4 is a waveform diagram showing the input voltage to the transformer device 1 at the top and the input current at the bottom.
Figure 5 is a waveform diagram showing the voltage v _m at the intermediate stage of the _transformer, the current i _m respectively. In practice, this is constituted by a pulse train by switching, and the waveform as a whole is shown as a whole.
Further, FIG. 6 is a waveform diagram in which the upper side shows (the envelope of) the output voltage from the transformer device 1 and the lower side shows (the envelope of) the output current. As apparent from the comparison of FIG. 4 and FIG. 6, the voltage is transformed to 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 has a pre-stage circuit including the switches S _r1 and S _b1 and the capacitors C1 and C2, and the switches S _r2 and S _b2 and the inductor It has a post-stage circuit configured by L1 and L2. The pre-stage circuit includes a plurality of capacitors C1 and C2 connected in series with each other and receiving an input voltage from AC power supply 2, and voltages applied to each of capacitors C1 and C2 are turned on / off of switches S _r1 and S _b1 . It becomes a circuit which changes and outputs one capacitor which becomes object by turning off and inverting the polarity. Similarly, the rear stage circuits are connected in series to each other, and the plurality of inductors L1 and L2 receiving the input voltage from the front stage circuit and the voltage applied to each of the inductors L1 and L2 are connected to the switches S _r2 and S _b2 It is a circuit which outputs while inverting the polarity while switching one target inductor by turning on / off the switch.

  In order to perform a transformation function as a transformation device, at least one of the front stage circuit and the rear stage circuit needs to be the above-mentioned circuit. However, there are other variations of the circuit (details will be described later).

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

FIG. 8 is a waveform diagram showing the input voltage to the transformer device 1 of the second example at the top and the input current at the bottom. Further, FIG. 9 is a waveform diagram in which the upper side represents (the envelope of) the output voltage from the transformer device 1 and the lower side represents (the envelope of) the output current. As apparent from the comparison of FIGS. 8 and 9, the voltage is transformed fourfold, and the current is reduced to 1⁄4 accordingly.
Thus, the transformer device 1 shown in FIG. 1 or FIG. 7 has input / output reversibility.

<< premise 3rd example >>
FIG. 10 is a circuit diagram showing a transformer device 1 according to a third example. The transformer device 1 differs from that of FIG. 1 in the arrangement of the switches S _r1 , S _r2 , S _b1 and S _b2 , but the other configuration is the same as that of FIG. 1. That is, in FIG. 10, the switches S _b2 and S _r2 on the side of the inductors L1 and L2 are upside down with _respect to 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. The pair of switches S _r1 and S _{r2 and} the pair of switches S _b1 and S _b2 operate so as to be alternately turned on alternately. 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 reverse phase to the circuit of FIG.
According to such switch arrangement and operation, the phase of the output with respect to the input can be reversed as compared with the case of FIG.

<< premise example 4 >>
FIG. 11 is a circuit diagram showing a transformer device 1 according to a fourth example. In the transformer device 1, the former circuit is expanded in order to increase the transformation ratio. The basics of the pre-stage circuit are "16C" by making "2C" similar to that of FIG. 1 into eight stages. 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 purpose) are required. It is known that such a pre-stage circuit outputs Vin / 16 with respect to the input voltage Vin. The post-stage circuit is similar to that of FIG. 1 and includes switches S _r9 and S _b9 and inductors L1 and L2. The post-stage circuit outputs Vin / 32 to the input voltage Vin / 16.

<< Impedance of transformer equipment >>
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 a capacitor C3 is added to the former circuit and an inductor L3 is added to the latter circuit. Thus, although the capacitor C3 and the inductor L3 are added, since these elements do not contribute to the transformation, the transformation device 1 is also "2C2L" as a type. The capacitor C3 is provided for the purpose of insulation against low frequencies, and the inductor L3 is provided for the purpose of insulation against high frequencies. For example, the capacitances of C1, C2 and C3 are 4.7 μF.

<< Embodiment with transformer >>
Now, 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 an AC power supply 2 and a 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 front 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 side winding of the transformer 5 is the input voltage to the subsequent stage circuit. The other circuit configuration and circuit details are the same as in FIG. For example, the turns ratio 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 current flowing is measured by the current sensor 7 to obtain the impedance. The impedance is similarly determined for the transformer 1 (without a transformer) of FIG.

  The result was about 300Ω in the case of the transformer 1 of FIG. 12 (without a transformer) and about 20 MΩ in the case of the transformer 1 of FIG. 13 (with a transformer). Thus, the insulation performance of the input end-output end of the transformer device 1 can be significantly improved by inserting the transformer 5. Further, by setting the insertion position of the transformer 5 between the front stage circuit and the rear stage 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 to be used is a high frequency transformer, and compact and lightweight transformers can be used. In addition, since the turns ratio can be set arbitrarily, a large transformation ratio can be realized while suppressing an increase in the size of the electric circuit.

  Also, by using the transformer 5, for example, a desired transformation ratio can be realized by adjusting the transformation ratio of the shortage of the combined value of each transformation ratio of the front stage circuit and the later stage circuit by the transformation ratio of the transformer it can. In this case, any desired transformation ratio can be accurately realized. That is, even if it is difficult to accurately adjust to the desired transformation ratio only with the front stage circuit and the rear stage circuit, the transformation ratio of the transformer can be set arbitrarily, so that the desired arbitrary transformation ratio can be realized accurately. . 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) transformation ratio, but even if the desired transformation ratio of the entire transformation device is (1 / odd), This can be achieved by setting the transformer transformation ratio. In a specific example, 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), Gives a transformation ratio of (1/15).

<< Modification of position of reactance element >>
Here, variations of the insertion position of the capacitor in the pre-stage circuit will be described. FIG. 15 is a circuit diagram showing the transformer device 1 in which the positions of the capacitors C1 and C2 are different in the case where attention is paid to the pre-stage circuit 1f of FIG. When the whole of the switches S _r1 and S _b1 connected in series with each other is viewed as a “switch series body”, one end of the switch series body is a node n11, the other end is a node n13, and the interconnection point is a node n12. There are the following examples other than FIG.

In FIG. 15, in the front-stage circuit 1f of (a), a capacitor C1 is provided in an electric path connecting the node n12 and the primary winding of the transformer 5, and a 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 an electric path 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 an electric path 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 an electric path connecting the connection point M1 and the primary winding of the transformer 5.

The manner of providing the capacitors shown in FIGS. 13 and 15 can be expressed as follows.
That is, at least two capacitors in the preceding circuit are required, and at least one capacitor needs to be inserted between each of 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.

  As another example, in (c) of FIG. 15, there are capacitors C1 and C2 between nodes n11 and n12, capacitor C2 between nodes n12 and n13, and node n11 and A capacitor C1 is present between n13 and n13.

  This rule can be applied similarly even if the pre-stage circuit is increased to "4C" and "6C" as well as "2C". 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 needs to be inserted between each node.

Next, variations of the insertion position of the inductor in the subsequent stage circuit will be described.
FIG. 16 is a circuit diagram showing the transformer device 1 in which the positions of the inductors L1 and L2 are different when focusing on the rear stage circuit 1r of FIG. When the whole of the switches S _r2 and S _b2 connected in series to each other is viewed as a “switch series body”, one end of the switch series body is a node n21, the other end is a node n23, and the interconnection point is a node n22. There are the following examples other than FIG.

In FIG. 16, in the post-stage circuit 1r of (a), an inductor L1 is provided in an electric path connecting a node n22 and a load, and an inductor L2 is provided between the node n23 and a connection point M2.
In the post-stage 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 path connecting the node n22 and the load.
In the post-stage 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 an electric path connecting the connection point M2 and the load.
In the post-stage 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 an electric path connecting the connection point M2 and the load.

The manner of providing the inductors shown in FIGS. 13 and 16 can be expressed as follows.
That is, at least two inductors are required in the post-stage circuit, and at least one should be inserted between each of the nodes n21, n22 and n23. For example, in FIG. 13, there is an inductor L1 between the nodes n21 and n22 via a 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.

  As another example, in (b) of FIG. 16, inductors L1 and L2 exist between node n21 and node n22, inductor L2 exists between nodes n22 and n23, and node n21 There is an inductor L1 between n and n23.

<< Transformer of 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, as shown in FIG. 11, the transformer device 1 for realizing a transformer ratio of 32: 1 has, for example, an eight-stage “16C2L” configuration of the front stage circuit. In this case, the number of circuit elements increases. However, as shown in FIG. 17, for example, if the 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, down to (Vin / 16) by the transformer, and finally output (Vin / 32) in the post-stage circuit. it can.

For example, in the case of a circuit with an alternating current input of several hundreds of volts and a power of about 1 kW, such a transformer device 1 has a volume of about 500 cm ³ for one stage of the front and rear circuits and about 200 cm ^{3 for} the isolation transformer. . In this case, the volume of the transformerless transformer device 1 of FIG. 11 is 500 × 8 + 500 × 1 + 200 × 0 = 4500 cm ³ , and the transformer-equipped transformer device 1 of FIG. 17 is 500 × 1 + 500 × 1 + 200 × 1 = 1200 cm ³ . That is, the volume of the transformer-equipped transformer device 1 of FIG. 17 is about 27% of the volume of the transformerless transformer device 1 of FIG.

活用 Use of midpoint tap transformer》
FIG. 18 is a circuit diagram showing a transformer 1 using a transformer 5 with a midpoint tap. For example, as apparent from comparison with FIG. 13, the inductor that should be present as the subsequent stage circuit is substituted (shared) with the winding of the transformer 5 with a center 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 is connected to both ends of the secondary side winding of the transformer 5. The load R is connected between the center tap of the secondary winding and a node n22 which is an 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 as, 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 a connection point M2 of the two inductors L1 and L2. Considering this, the rear stage circuit of FIG. 19 is the same as the rear stage circuit of FIG. Therefore, the transformer 5 performs transformation with the turn ratio of its own, while the subsequent circuit including the inductors L1 and L2 can perform transformation (1/2) of transformation (step-down).

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

In the case of FIG. 18 and FIG. 19, since two inductors of the post-stage circuit become unnecessary, the volume and weight can be greatly reduced. For example, the volume and weight of an inductor of several hundred μH and about 10 A are about 100 cm ³ and 0.3 to 0.5 kg per one, respectively. In this case, the inductor reduction can reduce the volume by about 20% and the weight by about 30%.

FIG. 20 is a circuit diagram showing a transformer 1 using a transformer 5 with a center point tap for both the primary side winding and the secondary side winding. In this case, the pre-stage circuit also has the same configuration as that of the post-stage circuit.
In this case, as compared with FIG. 18, the two capacitors of the pre-stage circuit are not required, so that the volume can be further reduced. For example, since the volume of a several hundred V withstand voltage, several μF capacitor is about 20 to 50 cm ³ per one, the volume can be expected to be reduced by about 10%. Such a transformer device 1 can also design the overall transformer ratio arbitrarily by designing the turns ratio of the transformer 5 arbitrarily. For example, if the transformation ratio of the entire circuit is 4: 1, it can be realized by setting the turns ratio of the transformation ratio to 4: 1. If the transformation ratio of the entire circuit is 8: 1, the transformation ratio of It can be realized by setting the turns ratio to 8: 1.

<< Variation of pre-stage circuit and post-stage circuit >>
There are various variations in the pre-stage circuit and the post-stage circuit, which will be supplementarily described below.
FIG. 21 is a block diagram showing a schematic configuration of the transformer device 1 as viewed from the whole. That is, the transformer device 1 is a pre-stage circuit provided between the power supply 2 and the load R and having 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. 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. The transformer 5 is interposed between the front stage circuit 1 f and the rear stage circuit 1 r.

FIG. 22 is a diagram showing a basic form of a circuit that can be selected as the pre-stage circuit 1 f.
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 a basic type, and there is also a further application type with regard to the position on the electric path where reactive elements (capacitors, inductors) are provided (for example, FIG. 15).

(F1) is the pre-stage circuit 1f shown in (a) of FIG.
That is, in (F1), both ends of a series body in which a pair of capacitors are connected in series at capacitor connection points are respectively connected to input port P1 and input port P2, and capacitor connection points are connected to output port P4. The first circuit located between the input port P1 and the output port P3 and the second switch located between the input port P2 and the output port P3 are switching circuits that alternately turn on by switching.

(F2) is a pre-stage circuit obtained by multi-staging a plurality of units, with the pre-stage circuit 1f shown in (b) of FIG. 22 as one unit. In order to achieve multistage, a capacitor is also required for the line directly connected to the output port P3.
That is, in (F2), input ports P1 and P2 of a plurality of units are connected in series with each other as one unit in which a capacitor is inserted in a line directly connected to output port P3 in the previous stage circuit of (F1). Is a pre-stage circuit in which the output ports P3 and P4 of are connected in parallel with each other.

(F3) is the pre-stage circuit 1f shown in (c) of FIG.
That is, in (F3), both ends of a series body formed by connecting a pair of inductors in series with each other at the inductor connection point are connected to the output port P3 and the output port P4, respectively, and the inductor connection point is connected to the input port P2, It 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 obtained by multi-staging a plurality of units, with the pre-stage circuit 1f shown in (d) of FIG. 22 as one unit. In order to achieve multistage, 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 one directly connected to the input port P1 with an inductor interposed therein is taken as one unit, and the input ports P1 and P2 of a plurality of units are connected in series with one another. It is a pre-stage circuit in which P3 and P4 are connected in parallel to each other.

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

FIG. 23 is a diagram showing a basic form of a circuit which can be selected as the subsequent stage circuit 1r. However, what is shown here is a basic type, and there is a further application type as to the position on the electric path where reactive elements (capacitors, inductors) are provided (for example, FIG. 16).
One of the following (R1) to (R5) can be selected as the post-stage circuit of the transformer device 1.

(R1) is a post-stage circuit 1r shown in (a) of FIG.
That is, in (R1), both ends of a series body formed by connecting a pair of inductors in series with each other at the inductor connection point are respectively connected to the input port P5 and the input port P6, and the inductor connection point is connected to the output port P8, It is a post-stage circuit in which the first switch located between the input port P5 and the output port P7 and the second switch located 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 (b) of FIG. In order to achieve multistage, 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 to each other as one unit in which a line directly connected to the output port P7 in the rear stage circuit of (R1) Of the output ports P7 and P8 are connected in parallel with each other.

(R3) is the post-stage circuit 1r shown in (c) of FIG.
That is, in (R3), both ends of a series body in which a pair of capacitors are connected in series at capacitor connection points are respectively connected to output port P7 and output port P8, and capacitor connection points are connected to input port P6. It 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 (d) of FIG. In order to achieve multistage, a capacitor is also required for the line directly connected to the input port P5.
That is, (R4) connects the input ports P5 and P6 of a plurality of units in series with each other as one unit in which a capacitor is inserted in a line directly connected to the input port P5 in the subsequent stage circuit of (R3) Of the output ports P7 and P8 are connected in parallel with each other.

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

  And one of the front circuits (F1) to (F5) and any one of the rear circuits (R1) to (R5), and the front circuit is (F5). And the combination that the rear stage circuit is (R5) may be excluded as long as it excludes the combination.

As described above, various transformation ratios can be easily realized.
Furthermore, a plurality of transformer devices provided with any of the above-described pre-stage circuits and post-stage circuits may be configured in cascade. In this case, a large transformation ratio can be realized in both step-down and step-up.
In each of the above embodiments, the AC power supply 2 is used as the power supply. However, each of the transformer devices 1 described above is also applicable to a DC power supply, and can also be used as a DC / DC converter.

<< Variation of post-stage circuit in case of DC power supply >>
When the power supply is a DC power supply, any one of the following (R1) to (R5) can be selected as the rear stage circuit of the transformer device 1. The diode is a type 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 nonconductive (OFF).

(R1) is a post-stage circuit 1r shown in (a) of FIG.
That is, in (R1), both ends of a series body formed by connecting a pair of inductors in series with each other at the inductor connection point are respectively connected to the input port P5 and the input port P6, and the inductor connection point is connected to the output port P8, A second stage circuit in which a first diode between the input port P5 and the output port P7 and a second diode between the input port P6 and the output port P7 alternately conduct in accordance with the polarity of the input voltage is there.

(R2) is a post-stage circuit in which the post-stage circuit 1r shown in (b) of FIG. In order to achieve multistage, 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 to each other as one unit in which a line directly connected to the output port P7 in the rear stage circuit of (R1) Of the output ports P7 and P8 are connected in parallel with each other.

(R3) is the post-stage circuit 1r shown in (c) of FIG.
That is, in (R3), both ends of a series body in which a pair of capacitors are connected in series at capacitor connection points are respectively connected to output port P7 and output port P8, and capacitor connection points are connected to input port P6. A second stage circuit in which a first diode between the input port P5 and the output port P7 and a second diode between the input port P5 and the output port P8 alternately conduct in accordance with the polarity of the input voltage is there.

(R4) is a post-stage circuit in which the post-stage circuit 1r shown in (d) of FIG. In order to achieve multistage, a capacitor is also required for the line directly connected to the input port P5.
That is, (R4) connects the input ports P5 and P6 of a plurality of units in series with each other as one unit in which a capacitor is inserted in a line directly connected to the input port P5 in the subsequent stage circuit of (R3) Of the output ports P7 and P8 are connected in parallel with each other.

(R5) is the post-stage circuit 1r shown in (e) of FIG.
That is, (R5) is a post-stage circuit of a full bridge circuit which is constituted by four diodes and which is inputted from the input port P5, P6 and outputted from the output port P7, P8.

  In addition, as for the direction of the diode in (a)-(d) of FIG. 24, each diode may be reverse direction to illustration (anode * cathode is reverse).

As described above, when the power supply is a direct current power supply, the circuit variation in the subsequent stage increases, and first, as in the case of the alternating current power supply, any one of the front stage circuits (F1) to (F5) of FIG. And any one of the subsequent circuits (R1) to (R5) in FIG. 23 and excluding the combination in which the former circuit is (F5) and the latter circuit is (R5). It may be a device.
Further, it is configured to include any one of the pre-stage circuits (F1) to (F5) of FIG. 22 and any one of the post-stage circuits (R1) to (R5) of FIG. Any combination of the circuit (F5) and the subsequent circuit (R5) may be excluded as long as it excludes the combination.

Summary
As described above, in summary, the transformer device disclosed as an embodiment of the present invention is a transformer device provided between a low frequency power source having a frequency of direct current or commercial alternating current and a load. The transformer device includes a front stage circuit and a rear stage circuit, and a transformer is interposed between an output end of the front stage circuit and an input end of the rear stage circuit. The front stage circuit and the rear stage circuit each have a plurality of switches, and alternately switch the output polarity with respect to the input by high frequency switching.

  Then, at least one of the front stage circuit and the rear stage circuit is formed by connecting a plurality of switches which are multiples of 2 in series with each other, and the odd numbered switches and the even numbered switches as viewed from either end of the series body The switch series body which turns on alternately is provided.

  In addition, when the connection points of each switch in the switch series and the two end points of the switch series are regarded as a total of m nodes from one end of the switch series in the order of 1 to m, they are extracted from the odd nodes. A first electric path as a collection destination of the plurality of electric paths, a second electric path as one electric path drawn from an even node or a plurality of electric paths as a collection target, and a third one drawn out from one end of the switch series body There is an electrical path and a fourth electrical path drawn from the other end.

  The reactance element is at least one corresponding to at least (m-1) of m nodes between the odd node and the first electric path and between the even node and the second electric path. It is provided as it exists. Then, one of the pair of electric paths of the first and second electric paths and the pair of electric paths of the third and fourth electric paths is an input, and the other is an output.

For example, referring to FIG. 13 for a general description of the above-mentioned circuit, etc., in the pre-stage circuit, the connection point (n12) of each switch in the switch series (S _r1 , S _b1 ) and both ends of the switch series When a point (n11, n13) is regarded as a total of m (3 here) nodes and viewed in the order of 1 to m (1 to 3) from any one end side of the switch series body, an odd node (n11, n13) Or a plurality of electric paths as a collection destination of a plurality of electric paths drawn out from (a) from the connection point M1 to the primary winding of the transformer 5 and one electric path drawn out from the even node (n12) A second electric path (an electric path from the node n12 to the primary winding of the transformer 5) as a collection destination of the electric paths, and a third electric path (an electric path from the node n11 to the AC power supply 2) drawn out from one end of the switch series body; And a fourth electric path (an electric path 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) (m-1) of the m nodes between the odd node and the first electric path and between the even node and the second electric path. Here, there are at least one corresponding to two) nodes (n11, n13). Then, one of the pair of electric paths of the first and second electric paths and the pair of electric paths of the third and fourth electric paths (here, the latter) is an input, and the other (here, the former) is an output.

On the other hand, in the post-stage circuit of FIG. 13, there are a total of m (3 here) of interconnection points (n22) of the switches in the switch series body (S _r2 , S _b2 ) and both points (n21, n23) of the switch series body. As one node of the switch series body, viewed from any one end side of the switch series body in the order of 1 to m (1 to 3), the first as a collection destination of a plurality of electric paths drawn from the odd node (n21, n23) The electric path (the electric path from the connection point M2 to the load R) and the second electric path (the electric path from the node n22 to the load R) which is one electric path drawn from the even node (n22) or a plurality of electric paths And a third electric path (an electric path from the node n21 to the secondary winding of the transformer 5) drawn from one end of the switch series body, and a fourth electric path drawn from the other end (secondary winding of the transformer 5 from the node n23). There is an electrical path to the wire).

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

  The same relationship applies to other circuit variations.

  In the transformer device provided with such a circuit configuration, at least one of the pre-stage circuit and the post-stage circuit including the plurality of reactance elements can perform transformation only by the electric circuit instead of the electromagnetic induction. Also, the transformer can maintain electrical insulation between the primary and secondary and can perform transformation at a desired transformation ratio. By such complex transformation, a large transformation ratio can be realized while securing the electrical insulation between the input and the output.

"Supplementary Note"
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown by the claim, and it is intended that the meaning of a claim and equality and all the changes within the range are included.

DESCRIPTION OF SYMBOLS 1 transformer device 1 f pre-stage circuit 1 _r post-stage circuit 2 AC power supply, power supply 3 switching control unit 4 switching 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, node n11, n12, n13, n21, n22, n23 node P1 to P8 port R load

Claims (4)

A transformer device provided between a load and a low frequency power supply having a frequency of direct current or commercial alternating current,
A front-stage circuit and a rear-stage circuit, each circuit having a plurality of switches, and alternately reversing the polarity of the output with respect to the input by high frequency switching;
A transformer interposed between an output end of the front stage circuit and an input end of the rear stage circuit;
At least one of the pre-stage circuit and the post-stage circuit has a basic circuit configuration as follows:
A switch series body in which a plurality of switches which are multiples of 2 are connected in series with each other, and odd numbered switches and even numbered switches are alternately turned on when viewed from either end of the series.
When the mutual connection point of each switch in the switch series and the two end points of the switch series are a total of m nodes, when viewed in the order of 1 to m from any one end side of the switch series, A first electrical path as a collection destination of a plurality of electrical paths to be drawn out, and a second electrical path as a single electrical path drawn from an even node or a plurality of electrical paths as a collection destination;
A third electric path drawn out from one end of the switch series body, and a fourth electric path drawn out from the other end;
At least one of the m nodes corresponding to at least (m-1) nodes between the odd node and the first electric path and between the even node and the second electric path. A reactance element provided to be present individually,
A transformer device, wherein one of the pair of electric paths of the first electric path and the second electric path and the electric path of the third electric path and the electric path of the fourth electric path is an input and the other is an output.   The secondary winding of the above-mentioned transformer has a middle point tap, and from the middle point tap to one end and the other end of the secondary side winding are respectively also the reactance elements in the latter stage circuit. Transformer equipment.   The primary side winding of the transformer has a middle point tap, and one end and the other end of the first side winding from the middle point tap are also the reactance elements in the front stage circuit, respectively. The transformer device according to Item 2.   The desired transformation ratio is realized by adjusting the transformation ratio of the shortage of the combined value of the transformation ratio of each of the pre-stage circuit and the post-stage circuit by the transformation ratio of the transformer. The transformer device according to item 1.

Images