JP6821266B2 - Power converter - Google Patents

Description

Embodiments of the present invention relate to a power converter.

There is a parallel multiplex type power converter in which a plurality of converters are connected in parallel. Each converter has a switching element, and by switching the switching element, the power on the primary side of direct current or alternating current is converted to the power on the secondary side of direct current, or vice versa. A charge storage element (DC capacitor) is provided on the secondary side of each converter. Therefore, a plurality of LC loops are formed on the secondary side by each charge storage element and the wiring inductance, and a resonance current is generated in these loops with switching.

When an LC loop having a resonance point near an integral multiple of the switching frequency exists, a particularly large resonance current may be generated in the loop. Resonant current is a factor that causes overheating of wiring and charge storage elements. For this reason, it becomes necessary to increase the size of various parts, which hinders the miniaturization and cost reduction of each converter.

Countermeasures against the resonance current flowing in the LC loop include, for example, reduction of the voltage change rate (dV / dt) due to an increase in the gate resistance of the switching element, insertion of a damping resistor in or around the resonance generation loop, and the like. ..

Increasing the gate resistance not only deteriorates the conversion efficiency, but also has a limited effect depending on the resonance frequency band generated. On the other hand, the insertion of the damping resistor as seen in Patent Document 1 and the like can suppress the resonance current while suppressing the influence on the converter specifications, but causes an increase in steady power loss.

It has also been proposed that a resistor and a switching element are inserted in parallel with the resonance loop of the DC circuit and the switching element is appropriately controlled to achieve both suppression of resonance current and reduction of steady loss (for example, Patent Document). 2). However, in this method, the addition of switching elements complicates the system and increases the cost.

Further, a method of lowering the resonance frequency by inserting an inductor into the wiring for electrically connecting the DC circuits has also been proposed (see, for example, Patent Document 3). However, when this method is applied to a parallel multiplex type power converter, a large DC current flows through the inductor to be inserted, which requires a large inductor, which leads to an increase in the size of the power converter.

Therefore, in the parallel multiplexing type power conversion device, it is desired to be able to suppress the resonance current flowing in the LC loop with a simple configuration.

Japanese Unexamined Patent Publication No. 2005-102444 Patent No. 3801085 Patent No. 5972635

An embodiment of the present invention provides a power conversion device capable of suppressing a resonance current with a simple configuration.

According to an embodiment of the present invention, there is provided a power converter including a plurality of converters, a plurality of charge storage elements, a common line, and a plurality of wirings. The plurality of converters have a switching element, and by switching the switching element, the power on the primary side of direct current or alternating current is converted into the power on the secondary side of direct current, or vice versa. The plurality of charge storage elements are provided on the secondary side of each of the plurality of converters. The common line is provided on the secondary side of the plurality of converters. In the plurality of wirings, each of the plurality of converters and the plurality of charge storage elements is connected to the common line, and the secondary sides of the plurality of converters are connected in parallel. The plurality of converters are bridge circuits, and when the switching frequency of the switching element is fc, the number of the plurality of converters is n, and the number of legs of the plurality of converters is p, the plurality of converters. The wiring inductance of the wiring is such that the resonance frequencies of the plurality of loop circuits formed by the plurality of charge storage elements, the common line, and the plurality of wirings are brought close to an integral multiple of n × p × fc. It is individually adjusted.

A power conversion device capable of suppressing a resonance current with a simple configuration is provided.

It is a block diagram which shows typically the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. 3 (a) to 3 (c) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. 4 (a) and 4 (b) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. 9 (a) to 9 (c) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. 10 (a) and 10 (b) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. 13 (a) to 13 (c) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. 14 (a) and 14 (b) are graphs showing an example of the characteristics of the power conversion device according to the embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a graph which shows an example of the characteristic of the power conversion apparatus which concerns on embodiment. It is a block diagram which shows typically the modification of the power conversion apparatus which concerns on embodiment. It is a block diagram which shows typically the modification of the power conversion apparatus which concerns on embodiment. It is a block diagram which shows typically the modification of the power conversion apparatus which concerns on embodiment.

Hereinafter, each embodiment will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between the parts, and the like are not necessarily the same as the actual ones. Further, even when the same parts are represented, the dimensions and ratios may be different from each other depending on the drawings.
In addition, in the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a block diagram schematically showing a power conversion device according to an embodiment.
As shown in FIG. 1, the power conversion device 10 includes a plurality of converters 21 to 23, a plurality of charge storage elements 31 to 33, common lines 41 and 42, and a plurality of wirings 51 to 56. ..

The plurality of converters 21 to 23 have switching elements 101 and 102, and by switching the switching elements 101 and 102, the power on the primary side of DC or AC is converted to the power on the secondary side of DC, or vice versa. Perform the conversion. The converters 21 to 23 have, for example, a plurality of switching elements 101 and 102.

The plurality of charge storage elements 31 to 33 are provided on the secondary side of each of the plurality of converters 21 to 23. The common lines 41 and 42 are provided on the secondary side of the plurality of converters 21 to 23. The plurality of wirings 51 to 56 connect the plurality of converters 21 to 23 and the plurality of charge storage elements 31 to 33 to the common lines 41 and 42, respectively, and connect the secondary sides of the plurality of converters 21 to 23 in parallel. Connecting.

As described above, the power conversion device 10 includes a parallel multiplexing type power conversion device in which the secondary sides of a plurality of converters 21 to 23 are connected in parallel. In such a parallel multiplex type power converter, it is possible to relatively easily increase the capacity by increasing the number of converters connected in parallel. In this example, an example in which three converters 21 to 23 are connected in parallel is shown. The number of converters connected in parallel is not limited to three, and may be any number.

In this example, the power on the primary side is DC power. The power conversion device 10 has a pair of terminals 61p and 61n on the primary side and a pair of terminals 62p and 62n on the secondary side. The terminals 61p and 61n are electrically connected to the DC power system on the primary side. The terminals 62p and 62n are electrically connected to the DC power system on the secondary side. The power system on the primary side is, for example, a DC power supply. The power system on the secondary side is, for example, a DC power supply or a DC load. Further, the terminals 61p and 62p are connected to the high potential side of the DC power system. The terminals 61n and 62n are connected to the low potential side of the DC power system. The terminal 62n is electrically connected to the terminal 61n via the wiring 64.

The converter 21 has two switching elements 101 and 102 connected in series and two rectifying elements 111 and 112 connected in antiparallel to each of the two switching elements 101 and 102. For the switching elements 101 and 102, for example, a power semiconductor such as an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET is used. The rectifying elements 111 and 112 are so-called freewheeling diodes.

One main terminal (for example, a collector) of the switching element 101 is electrically connected to the terminal 62p on the secondary side via the wiring 51 and the common line 41. The other main terminal (for example, an emitter) of the switching element 101 is electrically connected to one main terminal of the switching element 102. The other main terminal of the switching element 102 is electrically connected to the terminal 62n on the secondary side via the wiring 52 and the common line 42. The connection points of the switching elements 101 and 102 are electrically connected to the terminal 61p on the primary side via the DC inductor 66 and the wiring 68.

In this way, the converter 21 electrically connects both ends of the two switching elements 101 and 102 to the pair of terminals 62p and 62n on the secondary side, and connects the connection points of the two switching elements 101 and 102 to the primary side. It is a half-bridge circuit electrically connected to the terminal 61p on the high potential side of the above. In other words, the converter 21 is a bidirectional chopper circuit.

The converter 21 converts the DC power supplied from the primary side power system into the DC power corresponding to the secondary side power system, supplies the converted DC power to the secondary side power system, and at the same time, The DC power supplied from the power system on the next side is converted into DC power corresponding to the power system on the primary side, and the converted DC power is supplied to the power system on the primary side. For example, the converter 21 boosts the DC power on the primary side and supplies it to the secondary side, and lowers the DC power on the secondary side and supplies it to the primary side. Since the configurations of the converters 22 and 23 are substantially the same as the configurations of the converter 21, detailed description thereof will be omitted.

The charge storage elements 31 to 33 are connected in parallel to the secondary side of the converters 21 to 23. In other words, the charge storage elements 31 to 33 are connected in parallel to the switching elements 101 and 102. The charge storage elements 31 to 33 are, for example, DC capacitors.

The common line 41 is electrically connected to the terminal 62p on the secondary side. The common line 42 is electrically connected to the terminal 62n on the secondary side. The common lines 41 and 42 are, for example, plate-shaped. The common lines 41 and 42 are, for example, parallel flat plate-shaped busbars.

One end of the wiring 51 is electrically connected to the high potential side of the secondary side of the converter 21. The other end of the wiring 51 is electrically connected to the common line 41. One end of the wiring 52 is electrically connected to the low potential side of the secondary side of the converter 21. The other end of the wiring 52 is electrically connected to the common line 42. The wirings 51 and 52 are, for example, plate-shaped. The wirings 51 and 52 are, for example, parallel flat plate-shaped busbars. Since the configurations of the wirings 53 to 56 are substantially the same as the configurations of the wirings 51 and 52, detailed description thereof will be omitted.

The wiring 51 includes a wiring inductance Ls1. The wiring 53 includes a wiring inductance Ls2. The wiring 55 includes a wiring inductance Ls3. The common line 41 includes wiring inductances Ls4 and Ls5. The wiring inductances Ls1 to Ls5 do not exist as components, but are parasitic inductances of the wirings 51, 53, 55, and the common line 41. The wiring inductance Ls4 is the wiring inductance of the portion of the wiring inductance of the common line 41 between the wiring 51 and the wiring 53. The wiring inductance Ls5 is the wiring inductance of the portion of the wiring inductance of the common line 41 between the wiring 53 and the wiring 55.

The wiring inductance of the wiring 52 is substantially the same as the wiring inductance of the wiring 51. The wiring inductance of the wiring 54 is substantially the same as the wiring inductance of the wiring 53. The wiring inductance of the wiring 56 is substantially the same as the wiring inductance of the wiring 55. The wiring inductance of the common line 42 is substantially the same as the wiring inductance of the common line 41.

In the power conversion device 10, the wiring inductances of the plurality of wirings 51 to 56 are individually adjusted. The wiring inductance of any one of the plurality of wirings 51, 53, 55 on the high potential side is different from the other wiring inductance. The wiring inductances of the wirings 51, 53, and 55 may be different from each other, or only one of the three may be different. Similarly, the wiring inductance of any one of the plurality of wirings 52, 54, 56 on the low potential side is different from the other wiring inductance.

More specifically, the power conversion device 10 adjusts the wiring inductance of the wirings 51 to 56 as follows. The switching frequency of the switching elements 101 and 102 is defined as "fc". Let the number of the plurality of converters 21 to 23 be "n". More specifically, "n" is the number of converters connected in parallel. Therefore, in this example, n = 3. Let "p" be the number of legs of a plurality of converters 21 to 23 which are bridge circuits. In this example, the converters 21 to 23 are half-bridge circuits, so p = 1. When the converters 21 to 23 are single-phase full-bridge circuits, p = 2, and when the converters 21 to 23 are three-phase full-bridge circuits, p = 3. Further, a plurality of loop circuits formed by a plurality of charge storage elements 31 to 33, common lines 41 and 42, and a plurality of wirings 51 to 56 are referred to as "LPC".

When "fc", "n", "p", and "LPC" are set as described above, the wiring inductance of the plurality of wirings 51 to 56 sets the resonance frequency of each of the plurality of loop circuits LPC to p × fc. Individually adjusted so as to be offset from an integral multiple of or closer to an integral multiple of n × p × fc.

As a result, the power conversion device 10 can suppress the generation of resonance current in each loop circuit LPC. Resonance current can be suppressed with a simple configuration without the need for additional components such as switching elements and damping resistors.

The wiring inductance of the wirings 51 to 56 can be realized by changing the wiring length, shape, and the like. The wiring inductances of the common lines 41 and 42 and the wirings 51 to 56 can be obtained by, for example, an analysis system using the finite element method. The resonance frequency of the loop circuit LPC can be obtained by, for example, a circuit simulator that reflects the wiring inductance analysis result.

Hereinafter, the relationship between the wiring inductance of the wirings 51 to 56 and the resonance current will be described.
2 and 3 (a) to 3 (c) are graphs showing an example of the characteristics of the power conversion device according to the embodiment.
2 and 3 (a) to 3 (c) show substantially each of the wiring inductance Ls1 of the wirings 51 and 52, the wiring inductance Ls2 of the wirings 53 and 54, and the wiring inductance Ls3 of the wirings 55 and 56. An example of the characteristics when they are made equal (when Ls1 = Ls2 = Ls3) is shown.

FIG. 2 shows the relationship between the current effective values of the currents iC1 to iC3 flowing through the charge storage elements 31 to 33 and the switching duty ratio of the switching elements 101 and 102.
3 (a) to 3 (c) show the relationship between the current effective values of the currents iC1 to iC3 flowing through the charge storage elements 31 to 33 and the time.

As shown in FIG. 2, the current effective values of the currents iC1 to iC3 depend on the switching duty ratio of the switching elements 101 and 102. In particular, for the currents iC1 and iC3, peaks are observed near Duty = 0.31 and 0.44. Further, in FIGS. 3 (a) to 3 (c), the currents iC1 and iC3 contain a large amount of a component of 4800 Hz, and this component is continuously flowing not only immediately after the occurrence of switching but also continuously. It can be seen that resonance caused by the charge storage elements 31 to 33 and the wiring inductances Ls1 to Ls5 occurs in the DC circuit, causing an increase in the currents iC1 and iC3.

4 (a) and 4 (b) are graphs showing an example of the characteristics of the power conversion device according to the embodiment.
4 (a) and 4 (b) show direct current from the DC portion of each of the converters 21 to 23 under the same conditions (Ls1 = Ls2 = Ls3) as in FIGS. 2 and 3 (a) to 3 (c). The frequency characteristics (around 4 kHz to 10 kHz) of the impedance in anticipation of the entire circuit are shown. Impedance measurement points are terminal portions on the secondary side of each of the converters 21 to 23, as represented by arrows A1-A2 in FIG. FIG. 4A is a frequency characteristic of the impedance of the converters 21 and 23, and FIG. 4B is a frequency characteristic of the impedance of the converter 22.

As shown in FIGS. 4 (a) and 4 (b), the DC circuit has a resonance point in the vicinity of 4800 Hz to 5400 Hz. As described above, even when the wiring inductances Ls1 to Ls3 of the wirings 51 to 56 from the converters 21 to 23 to the common lines 41 and 42 are substantially equal, the wiring inductances Ls4 and Ls5 of the common lines 41 and 42 are present. In addition, the impedances seen from the converters 21 to 23 are not equal.

5 to 7 are graphs showing an example of the characteristics of the power conversion device according to the embodiment.
FIG. 5 shows an example of the switching current flowing into the DC circuit of each of the converters 21 to 23. In FIG. 5, as an example of the switching current, only the alternating current component when the switching frequency is fc = 600 Hz and the duty is 0.45 is shown.
FIG. 6 shows the results of FFT (Fast Fourier Transform) analysis of the switching current shown in FIG.
FIG. 7 shows the result of FFT analysis of the current iC1 of FIG. 3 (a).

As shown by the switching current shown in FIG. 5 and the FFT analysis result shown in FIG. 6, the switching current generally contains a large amount of harmonic components having a switching frequency fc (600 Hz this time) as a fundamental wave. When the converters 21 to 23 are not a half-bridge circuit but a full-bridge circuit having a leg number p of 2 or 3, p × fc is the fundamental wave. When Duty = 0.45 shown as an example, there is a non-negligible current component at 4800 Hz, which is the 8th harmonic, and this frequency is close to the resonance point in FIG. 4 (a). Therefore, it is considered that a large resonance current is brought about in the converters 21 and 23 shown in FIGS. 2 and 3.

As shown in FIG. 7, in the FFT analysis result of the current iC1, the current component near 4800 Hz is dominant so as to support the above mechanism.

On the other hand, as shown in FIG. 4B, the resonance point of the converter 22 is higher than that of the converters 21 and 23, and is around 5400 Hz of the 9th harmonic. As shown in the FFT analysis result of the switching current in FIG. 6, the harmonic component near 5400 Hz is sufficiently small. Therefore, it is considered that the resonance current is not so remarkable in the converter 22.

8, 9 (a) to 9 (c), 10 (a), 10 (b), and 11 are graphs showing an example of the characteristics of the power conversion device according to the embodiment.
8 and 9 (a) to 9 (c) are examples in which the wiring inductances Ls1 to Ls3 are all reduced to 70% from the situations shown in FIGS. 2 and 3 (a) to 3 (c). Represent.
10 (a) and 10 (b) show the frequency characteristics of the impedance of the DC circuit in the states of FIGS. 8 and 9 (a) to 9 (c).
FIG. 11 shows the result of FFT analysis of the current iC2 of FIG. 9B.

As shown in FIGS. 8, 9 (a) to 9 (c), 10 (a), 10 (b), and 11, the resonance frequency is increased as a whole due to the decrease in the wiring inductances Ls1 to Ls3. The frequency rises to 5300 Hz to 6000 Hz. Therefore, it is possible to reduce the resonance current due to the switching current component of 4800 Hz. On the other hand, since the resonance point of the impedance seen from the converter 22 approaches 6000 Hz, which is the 10th harmonic of the switching current, a large amount of 6000 Hz current flows in the converter 22 of FIG. 9, and the resonance current is significantly reduced. Not done.

12, FIGS. 13 (a) to 13 (c), 14 (a), 14 (b), and 15 are graphs showing an example of the characteristics of the power conversion device according to the embodiment.
In FIGS. 12 and 13 (a) to 13 (c), the wiring inductances Ls1 and Ls3 are set to 70% from the situations shown in FIGS. 2 and 3 (a) to 3 (c), while the wiring inductance is set to 70%. An example in which Ls2 is set to 140% is shown.
14 (a) and 14 (b) show the frequency characteristics of the impedance of the DC circuit in the states of FIGS. 12 and 13 (a) to 13 (c).
FIG. 15 shows the result of FFT analysis of the current iC2 of FIG. 13 (b).

From the examination results so far, when the wiring inductances Ls1 to Ls3 of the wirings 51 to 56 from the converters 21 to 23 to the common lines 41 and 42 are adjusted collectively, the wiring impedances Ls4 and Ls5 of the common lines 41 and 42 are Due to the existence, the resonance points of the impedances seen from the converters 21 to 23 are slightly different. Therefore, as a result, it can be seen that a large resonance current is likely to be generated in any of the converters 21 to 23.

Therefore, the wiring inductances Ls1 to Ls3 are individually adjusted as in the power conversion device 10 according to the present embodiment. As shown in FIG. 12, when the wiring inductances Ls1 and Ls3 are set to 70% and the wiring inductance Ls2 is set to 140%, the currents iC1 to iC3 are sufficiently suppressed to less than 100A for a wide duty ratio. It has been realized.

Further, as shown in FIGS. 14 (a) and 14 (b), as a result of adjusting the wiring inductances Ls1 to Ls3, all the resonance points of the converters 21 to 23 are in the vicinity of 5400 Hz. As a result, as shown in FIG. 15, the current components of 4800 Hz and 6000 Hz are reduced as compared with the peak current components of the examples shown in FIGS. 7 and 11, and the resonance current is reduced. It can be seen that the above has been achieved.

When Duty = 0.45, as shown in FIG. 6, the current component of 5400 Hz can be ignored. On the other hand, when the duty changes to 0.5 or the like, the component of 5400 Hz cannot be ignored. However, in the 3-parallel multiplex bidirectional chopper examined this time, the switching current component of 5400 Hz, which is the 9th harmonic, is a multiple of 3 even though the triangular wave carriers are shifted by 120 °. It becomes an in-phase component, and as a result, the effect that the resonance current is almost canceled occurs. In general, a frequency component that is an integral multiple of n × p × fc (= 3 × 1 × 600 = 1800 Hz) does not substantially appear in the DC circuit.

FIG. 16 is a graph showing an example of the characteristics of the power conversion device according to the embodiment.
In support of the above-mentioned resonance current cancellation phenomenon, FIG. 16 shows the FFT analysis result of the current iC1 in the 4-parallel multiplex bidirectional chopper. Since the switching current is substantially the same as that in FIG. 6, the current iC1 contains almost no component of 4800 Hz even though it contains a large amount of the component of 4800 Hz. It is considered that this is because 4800 Hz is the 8th harmonic and is a multiple of the parallel multiplex 4.

As described above, in the power conversion device 10 according to the present embodiment, by adjusting the wiring inductances Ls1 to Ls3 individually, it is simple without the need to add parts such as a switching element and a damping resistor. Resonance current can be suppressed by the configuration.

FIG. 17 is a block diagram schematically showing a modified example of the power conversion device according to the embodiment.
The same reference numerals are given to those having substantially the same functions and configurations as those of the above-described embodiment, and detailed description thereof will be omitted.
As shown in FIG. 17, the power conversion device 10a has three primary side terminals 61u, 61v, and 61w. In this example, the power on the primary side is three-phase AC power. In the power converter 10a, the converters 21 to 23 are provided corresponding to each phase of the three-phase AC power. Therefore, in this example, the number of converters 21-23 is a multiple of 3.

The connection points of the switching elements 101 and 102 of the converter 21 are electrically connected to the terminal 61u on the primary side via the AC inductor 66u. Similarly, the connection points of the switching elements 101 and 102 of the converter 22 are electrically connected to the terminal 61v on the primary side via the AC inductor 66v. The connection points of the switching elements 101 and 102 of the converter 23 are electrically connected to the terminal 61w on the primary side via the AC inductor 66w.

In this way, the converters 21 to 23 electrically connect both ends of the two switching elements 101 and 102 to the pair of terminals 62p and 62n on the secondary side, and connect the connection points of the two switching elements 101 and 102. It is a half-bridge circuit electrically connected to one phase terminal (any of terminals 61u, 61v, 61w) of three-phase AC power.

Also in the power conversion device 10a configured in this way, by individually adjusting the wiring inductances Ls1 to Ls3, it is not necessary to add parts such as a switching element and a damping resistor as in the above embodiment. Resonance current can be suppressed with a simple configuration.

FIG. 18 is a block diagram schematically showing a modified example of the power conversion device according to the embodiment.
As shown in FIG. 18, the power converter 10b has two primary side terminals 61u and 61v. In this example, the power on the primary side is single-phase AC power.

In the power converter 10b, the converter 21 has four switching elements 101-104 and four rectifying elements 111-114. The converter 21 is a two-leg full-bridge circuit in which four switching elements 101 to 104 are fully bridge-connected.

One end of the switching elements 101 and 102 connected in series is electrically connected to the terminal 62p on the secondary side. The other ends of the switching elements 101 and 102 are electrically connected to the terminals 62n on the secondary side. The connection point between the switching element 101 and the switching element 102 is electrically connected to the terminal 61u on the primary side via the AC inductor 66u.

One end of the switching elements 103 and 104 connected in series is electrically connected to the terminal 62p on the secondary side. The other ends of the switching elements 103 and 104 are electrically connected to the terminals 62n on the secondary side. The connection point between the switching element 103 and the switching element 104 is electrically connected to the terminal 61v on the primary side.

The rectifying elements 111 to 114 are connected to the switching elements 101 to 104 in antiparallel. Since the configurations of the converters 22 and 23 are substantially the same as the configurations of the converter 21, detailed description thereof will be omitted.

As described above, in the power converter 10b, the converters 21 to 23 electrically connect both ends of the two legs to the pair of terminals 62p and 62n on the secondary side, and connect one midpoint of the two legs to the primary side. It is electrically connected to one of the pair of terminals 61u and 61v, and the midpoint of the other of the two legs is electrically connected to the other of the pair of terminals 61u and 61v on the primary side.

Also in the power conversion device 10b configured in this way, by individually adjusting the wiring inductances Ls1 to Ls3, it is not necessary to add parts such as a switching element and a damping resistor as in the above embodiment. Resonance current can be suppressed with a simple configuration.

FIG. 19 is a block diagram schematically showing a modified example of the power conversion device according to the embodiment.
As shown in FIG. 19, the power converter 10c has three primary side terminals 61u, 61v, 61w. In this example, the power on the primary side is three-phase AC power.

In the power converter 10c, the converter 21 includes six switching elements 101-106 and six rectifying elements 111-116. The converter 21 is a 3-leg full-bridge circuit in which six switching elements 101 to 106 are fully bridge-connected.

One end of the switching elements 101 and 102 connected in series is electrically connected to the terminal 62p on the secondary side. The other ends of the switching elements 101 and 102 are electrically connected to the terminals 62n on the secondary side. The connection point between the switching element 101 and the switching element 102 is electrically connected to the terminal 61u on the primary side via the AC inductor 66u.

One end of the switching elements 103 and 104 connected in series is electrically connected to the terminal 62p on the secondary side. The other ends of the switching elements 103 and 104 are electrically connected to the terminals 62n on the secondary side. The connection point between the switching element 103 and the switching element 104 is electrically connected to the terminal 61v on the primary side via the AC inductor 66v.

One end of the switching elements 105 and 106 connected in series is electrically connected to the terminal 62p on the secondary side. The other ends of the switching elements 105 and 106 are electrically connected to the terminals 62n on the secondary side. The connection point between the switching element 105 and the switching element 106 is electrically connected to the terminal 61w on the primary side via the AC inductor 66w.

The rectifying elements 111 to 116 are connected to the switching elements 101 to 106 in antiparallel. Since the configurations of the converters 22 and 23 are substantially the same as the configurations of the converter 21, detailed description thereof will be omitted.

As described above, in the power converter 10c, the converters 21 to 23 electrically connect both ends of the three legs to the pair of terminals 62p and 62n on the secondary side, and connect the midpoints of the three legs to the primary side. It is electrically connected to each of the pair of terminals 61u, 61v, and 61w.

Also in the power conversion device 10b configured in this way, by individually adjusting the wiring inductances Ls1 to Ls3, it is not necessary to add parts such as a switching element and a damping resistor as in the above embodiment. Resonance current can be suppressed with a simple configuration.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10, 10a-10c ... Power converter, 21-23 ... Converter, 31-33 ... Charge storage element, 41, 42 ... Common line, 51-56 ... Wiring, 61p, 61n, 61u, 61v, 61w ... Terminal, 62p, 62n ... Terminal, 64 ... Wiring, 66 ... DC inductor, 66u, 66v, 66w ... AC inductor, 68 ... Wiring, 101-106 ... Switching element, 111-116 ... Rectifier element

Claims (6)

A plurality of converters having a switching element and converting DC or AC primary power into DC secondary power or vice versa by switching the switching element.
A plurality of charge storage elements provided on the secondary side of each of the plurality of converters, and
A common line provided on the secondary side of the plurality of converters,
A plurality of wirings in which each of the plurality of converters and the plurality of charge storage elements is connected to the common line, and the secondary sides of the plurality of converters are connected in parallel.
With
The plurality of converters are bridge circuits.
The switching frequency of the switching element is fc.
Let n be the number of the plurality of converters.
When the number of legs of the plurality of converters is p,
The wiring inductance of the plurality of wirings brings the resonance frequencies of the plurality of loop circuits formed by the plurality of charge storage elements, the common line, and the plurality of wirings closer to an integral multiple of n × p × fc. Power converters that are individually tuned so that . The power on the primary side is DC power, and is
The plurality of converters have two switching elements connected in series, both ends of the two switching elements are electrically connected to a pair of terminals on the secondary side, and the two switching elements are connected. The power conversion device according to claim 1, which is a half-bridge circuit in which points are electrically connected to terminals on the high potential side on the primary side. The power on the primary side is three-phase AC power, and is
The plurality of converters are provided corresponding to each phase of the three-phase AC power, have two switching elements connected in series, and a pair of secondary sides at both ends of the two switching elements. The power conversion device according to claim 1, which is a half-bridge circuit that is electrically connected to a terminal and the connection point of the two switching elements is electrically connected to the terminal of one phase of the three-phase AC power. The power on the primary side is single-phase AC power, and is
The plurality of converters are a two-leg full-bridge circuit in which four switching elements are fully bridge-connected, and both ends of the two legs are electrically connected to a pair of terminals on the secondary side to form the two-leg. one midpoint and electrically connected to one of a pair of terminals of the primary side, said second pair of terminals of the leg and the other midpoint primary side of the other and electrically connected to that claim 1, wherein Power converter. The power on the primary side is three-phase AC power, and is
The plurality of converters are a three-leg full-bridge circuit in which six switching elements are fully bridge-connected, and both ends of the three-legs are electrically connected to a pair of terminals on the secondary side to form the three-legs. The power conversion device according to claim 1, wherein each midpoint is electrically connected to each of the three terminals on the primary side. A plurality of converters having a switching element and converting DC or AC primary power into DC secondary power or vice versa by switching the switching element.
A plurality of charge storage elements provided on the secondary side of each of the plurality of converters, and
A common line provided on the secondary side of the plurality of converters,
A plurality of wirings in which each of the plurality of converters and the plurality of charge storage elements is connected to the common line, and the secondary sides of the plurality of converters are connected in parallel.
With
Individually adjust the wiring inductance of the plurality of wires,
The power on the primary side is DC power, and is
The plurality of converters have two switching elements connected in series, both ends of the two switching elements are electrically connected to a pair of terminals on the secondary side, and the two switching elements are connected. A power converter that is a half-bridge circuit that electrically connects points to terminals on the high potential side on the primary side.

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