JP6341051B2 - 5-level power converter - Google Patents

Description

  The present invention relates to a DC-AC power converter and an AC-AC power converter that can output a multilevel voltage at the input and output.

  FIG. 11 (Patent Document 1) and FIG. 12 (Patent Document 2) show typical configuration examples of a conventional 5-level power converter.

  FIG. 11 shows a five-level power converter with three-phase output. Table 1 is an example of the switching pattern and output phase voltage VOUT-NP of the switching devices Su1 to Su10 of the five-level power converter shown in FIG.

  The output phase voltage VOUT-NP shown in Table 1 is a voltage between the output terminal OUT and the neutral point NP. Here, “1” in the table represents a state where the switching device is ON, and “0” represents a state where the switching device is OFF. Further, each applied voltage of the DC capacitors C1 to C4 is assumed to be E.

  FIG. 12 is a circuit configuration diagram showing a five-level power converter in Patent Document 2. In FIG. 12, only a one-phase output circuit is shown, but application to a multiphase circuit is also possible. Table 2 is an example of the switching pattern of the switching device and the output phase voltage VOUT-NP of the five-level power converter shown in FIG.

Here, “1” in the table represents the ON state of the switching device, and “0” represents the OFF state of the switching device. The applied voltage of the DC capacitors 6 ₁ and 6 ₂ is 2E, and the applied voltage of the DC capacitors C3 and C4 is E.

JP 2012-253927 A FU06958324_20051025

  However, in the five-level power converter shown in FIG. 11, when a voltage is output from the positive side of the main DC voltage to the output terminal OUT or from the negative side to the output terminal OUT, the number of conductions of the switching device is three. It is. This is explained by the fact that there are three switching devices in the ON state in all the switching patterns of Table 1.

  It is desirable in terms of the efficiency of the power conversion device that the conduction loss of the switching device can be reduced by reducing the number of conduction of the switching device.

When the 5-level power converter of FIG. 12 is used, as can be seen from Table 2, a voltage is output from the positive side of the main DC voltage to the output terminal OUT or from the negative side to the output terminal OUT. The number of conductions of the switching device is two. The conduction loss of the switching device can be reduced as compared with the configuration of FIG. However, in this circuit configuration, it is necessary to provide two DC capacitors C3 and C4 in a one-phase power converter in addition to the DC capacitors 6 ₁ and 6 ₂ .

For this reason, in the three-phase power converter, six DC capacitors C3 and C4 built in the power converter and two DC capacitors 6 ₁ and 6 ₂ are required, for a total of eight capacitors. In terms of miniaturization of the power converter, the circuit configuration of FIG. 12 having a large number of capacitors is not desirable.

  As described above, in the five-level power conversion device, it is a problem to reduce the number of conduction of the switching device, reduce the number of capacitors, reduce the conduction loss of the switching device, and reduce the size of the device. .

  The present invention has been devised in view of the above-described conventional problems, and one aspect thereof is a five-level power conversion that performs voltage conversion from a DC voltage to an AC voltage or voltage conversion from an AC voltage to a DC voltage. A first to fourth capacitor sequentially connected in series between the positive and negative electrodes of a DC voltage source; seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor; Ninth and tenth switching devices connected in series between both terminals of the capacitor, and third and fourth devices connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices. A common connection point of the switching device, the ninth and tenth switching devices, a fifth and a sixth switching device sequentially connected in series to the negative terminal of the DC voltage source, and a third and a fourth switching device A voltage selection circuit having first and second switching devices sequentially connected in series between the common connection point and the common connection point of the fifth and sixth switching devices. The common connection point is a neutral point, and the common connection point of the first and second switching devices is an output terminal.

  In another aspect, the present invention is a five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage, the first positive terminal of the DC voltage source and the first Second and third capacitors sequentially connected in series between the negative terminals, a first capacitor connected between the first positive terminal and the second positive terminal of the DC voltage source, a first negative terminal of the DC voltage source and the first A fourth capacitor connected between the two negative terminals, seventh and eighth switching devices sequentially connected in series between the second positive terminal of the DC voltage source and the common connection point of the second and third capacitors, , The ninth and tenth switching devices sequentially connected in series between the common connection point of the third capacitor and the second negative terminal of the DC voltage source, and the first positive terminal and the seventh and eighth switching devices of the DC voltage source. In order to the common connection point Third and fourth switching devices connected in series; fifth and sixth switching devices sequentially connected in series between the common connection point of the ninth and tenth switching devices and the first negative terminal of the DC voltage source; A voltage selection circuit having first and second switching devices sequentially connected in series between a common connection point of the third and fourth switching devices and a common connection point of the fifth and sixth switching devices. And the common connection point of the second and third capacitors is a neutral point, and the common connection point of the first and second switching devices is an output terminal.

  In another aspect, the present invention is a five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage, the first positive terminal of the DC voltage source and the first A first capacitor connected in series between the negative terminals, a fourth capacitor; a second capacitor connected between a second positive terminal of the DC voltage source and a common connection point of the first and fourth capacitors; , A third capacitor connected between the common connection point of the fourth capacitor and the second negative electrode terminal of the DC voltage source, and seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor; The ninth and tenth switching devices sequentially connected in series between both terminals of the third capacitor and the serial connection between the first positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices. Third and fourth Switching devices, fifth and sixth switching devices sequentially connected in series between the common connection point of the ninth and tenth switching devices and the first negative terminal of the DC voltage source, and the third and fourth switching devices A voltage selection circuit having first and second switching devices sequentially connected in series between the common connection point and the common connection point of the fifth and sixth switching devices. The common connection point is a neutral point, and the common connection point of the first and second switching devices is an output terminal.

  Further, as another aspect, a five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage, and sequentially connected in series between the positive and negative electrodes of the DC voltage source First to fourth capacitors, a seventh switching device sequentially connected in series between both terminals of the second capacitor, a first diode, and a second diode sequentially connected in series between both terminals of the third capacitor; A tenth switching device, a third terminal, a fourth switching device, a second diode, and a tenth switching device connected in series between a common connection point of the positive electrode terminal of the DC voltage source, the seventh switching device, and the first diode. The common connection point, the fifth and sixth switching devices sequentially connected in series to the negative terminal of the DC voltage source, and the third and fourth switching devices A voltage selection circuit having first and second switching devices sequentially connected in series between the connection point and the common connection point of the fifth and sixth switching devices, and common to the second and third capacitors. The connection point is a neutral point, and the common connection point of the first and second switching devices is an output terminal.

  Moreover, as one aspect thereof, the voltage selection circuit is three-phase connected in parallel to the first to fourth capacitors to obtain a three-phase AC output.

  As another aspect, the voltage selection circuit is connected in two phases in parallel to the first to fourth capacitors to provide a single-phase AC output.

  Further, as another aspect, a voltage selection circuit is further added in parallel with the first to fourth capacitors, and three-phase alternating current-three-phase alternating current conversion, or three-phase alternating current-single phase is added. It is characterized by AC conversion.

  Further, as another aspect, a voltage selection circuit is further added in two phases in parallel to the first to fourth capacitors, and is connected in parallel, and single phase AC-three phase AC conversion or single phase AC-single phase It is characterized by AC conversion.

  As another aspect, the seventh to eighth switching devices sequentially connected in series between both terminals of the second capacitor with respect to the first to fourth capacitors, and sequentially between both terminals of the third capacitor. Ninth and tenth switching devices connected in series; third and fourth switching devices sequentially connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices; The common connection point of the tenth switching device and the fifth and sixth switching devices sequentially connected in series to the negative electrode end of the DC voltage source are additionally connected, and common to the added third and fourth switching devices. A reactor and a DC power source are connected in series between the connection point and the common connection point of the fifth and sixth switching devices.

  As another aspect, the seventh to eighth switching devices sequentially connected in series between both terminals of the second capacitor with respect to the first to fourth capacitors, and sequentially between both terminals of the third capacitor. Ninth and tenth switching devices connected in series; third and fourth switching devices sequentially connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices; The common connection point of the tenth switching device and the fifth and sixth switching devices sequentially connected in series to the negative electrode end of the DC voltage source are additionally connected, and common to the added third and fourth switching devices. A reactor and a DC power source are connected in series between the connection point and the common connection point of the fifth and sixth switching devices.

  According to the present invention, in the five-level power conversion device, the number of conductions of the switching device is reduced, the number of capacitors is reduced, the conduction loss of the switching device is reduced, and the size of the device can be reduced. .

FIG. 2 is a circuit configuration diagram illustrating the five-level power conversion device according to the first embodiment. The circuit block diagram which shows the 5 level power converter device in Embodiment 2. FIG. FIG. 5 is a circuit configuration diagram showing a five-level power conversion device according to a third embodiment. FIG. 6 is a circuit configuration diagram showing a 5-level power conversion device according to a fourth embodiment. FIG. 6 is a circuit configuration diagram showing a five-level power conversion device according to a fifth embodiment. FIG. 10 is a circuit configuration diagram showing a five-level power conversion device according to a sixth embodiment. FIG. 10 is a circuit configuration diagram showing a five-level power conversion device according to a seventh embodiment. FIG. 10 is a circuit configuration diagram showing a five-level power conversion device according to an eighth embodiment. The circuit block diagram which shows the 5 level power converter device in Embodiment 9. FIG. FIG. 11 is a circuit configuration diagram showing a five-level power conversion device according to a tenth embodiment. The circuit block diagram which shows the 5-level power converter device in patent document 1. FIG. The circuit block diagram which shows the 5-level power converter device in patent document 2. FIG.

[Embodiment 1]
FIG. 1 is a circuit configuration diagram showing a five-level power converter according to the first embodiment. As shown in FIG. 1, first to fourth capacitors C1 to C4 are sequentially connected in series between a positive electrode P and a negative electrode N of a DC voltage source. The first to fourth capacitors C1 to C4 divide the DC voltage into four. The common connection point of the second and third capacitors C2 and C3 is a neutral point NP.

  The seventh and eighth switching devices S7 and S8 are connected in series between both terminals of the second capacitor C2, and the third and fourth switching devices S3 and S4 are connected between the positive electrode P and the common connection point of the seventh and eighth switching devices. Are sequentially connected in series.

  In addition, the ninth and tenth switching devices S9 and S10 are sequentially connected in series between both terminals of the third capacitor C3, and the fifth and sixth switching devices S5 are connected between the ninth and tenth switching devices S9 and S10 and the negative electrode N. , S6 are sequentially connected in series. The first and second switching devices S1 and S2 are sequentially connected in series between the common connection point of the third and fourth switching devices S3 and S4 and the common connection point of the fifth and sixth switching devices S5 and S6. . A common connection point of the first and second switching devices S1 and S2 is defined as an output terminal OUT. In addition, the voltage selection circuit 4 is comprised by 1st-10th switching device S1-S10.

  As described above, according to the first embodiment, it is possible to realize a five-level power converter with 10 switching devices per phase. In addition, a 2-in-1 module in which two general switching devices are connected in series can be used.

  Assuming that the voltages of the first to fourth capacitors C1 to C4 are E, Table 3 shows the relationship between the output phase voltage VOUT-NP to the output terminal OUT with the neutral point NP as a reference and the switching pattern.

  Here, each output phase voltage VOUT-NP and the current path of the switching pattern of Table 3 will be described below.

<Output phase voltage VOUT-NP = 2E>
The first and third switching devices S1 and S3 are turned on, the second and fourth to tenth switching devices S2 and S4 to S10 are turned off, and the current is neutral point NP → C2 → C1 → S3 → S1 → It flows through the path of the output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is 2E. In this switching pattern, the current conducts the two switching devices, the third and first switching devices S3 and S1.

<Output phase voltage VOUT−NP = E>
The first, fourth, and seventh switching devices S1, S4, and S7 are ON, and the second, third, fifth, sixth, and eighth to tenth switching devices S2, S3, S5, S6, and S8 to S10 are ON. Each becomes OFF, and the current flows through a path of neutral point NP → C 2 → S 7 → S 4 → S 1 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is E. In this switching pattern, the current conducts through the three switching devices of the seventh, fourth, and first switching devices S7, S4, and S1.

<Output phase voltage VOUT-NP = 0>
(1) The first, fourth, and eighth switching devices S1, S4, and S8 are ON, and the second, third, fifth, sixth, seventh, ninth, and tenth switching devices S2, S3, S5, respectively. Each of S6, S7, S9, and S10 is turned OFF, and the current flows through a route of neutral point NP → S8 → S4 → S1 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is zero. In this switching pattern, the current conducts through the three switching devices of the eighth, fourth, and first switching devices S8, S4, and S1.

  (2) The second, fifth, and ninth switching devices S2, S5, and S9 are ON, and the first, third, fourth, sixth, seventh, eighth, and tenth switching devices S1, S3, S4, Each of S6, S7, S8, and S10 is turned OFF, and the current flows through a route of neutral point NP → S9 → S5 → S2 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is zero. In this switching pattern, the current conducts through the three switching devices of the ninth, fifth and second switching devices S9, S5 and S2.

<Output phase voltage VOUT-NP = -E>
The second, fifth, and tenth switching devices S2, S5, and S10 are turned on, the first, third, fourth, and sixth to ninth switching devices S1, S3, S4, and S6 to SS9 are turned off. Flows along the path of neutral point NP → C3 → S10 → S5 → S2 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is -E. In this switching pattern, the current conducts the three switching devices of the tenth, fifth and second switching devices S10, S5 and S2.

<Output phase voltage VOUT-NP = -2E>
The second and sixth switching devices S2 and S6 are each ON, the first, third to fifth, and seventh to tenth switching devices S1, S3 to S5, and S7 to S10 are each OFF, and the current is neutral. It flows through a route of NP → C3 → C4 → S6 → S2 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is -2E. In this switching pattern, the current conducts the two switching devices of the sixth and second switching devices S6 and S2.

  As described above, the number of conductions of the switching device when outputting 2E and -2E is two, and the other switching patterns are three. Therefore, compared to the circuit configuration of FIG. 8, when 2E and -2E are output, the number of conductions of the switching device is reduced, and conduction loss can be reduced. That is, when outputting E, 0, -E, the number of conductions of the switching device is 3, which is the same as the circuit configuration shown in FIG. However, since the absolute value of the current increases when 2E or -2E is output under high power factor conditions, the power of Embodiment 1 reduces the number of conductions of the switching device when 2E or -2E is output. The converter has a great effect on reducing the conduction loss of the entire power converter, that is, improving the efficiency of the power converter.

  In addition, according to the first embodiment, since a five-level power conversion device can be realized with four DC capacitors and ten switching devices per phase, the size of the device can be reduced as compared with Patent Document 2. Is possible. In addition, since a general 2-in-1 module can be used, a small and highly efficient 5-level power converter can be realized.

[Embodiment 2]
FIG. 2 is a circuit configuration diagram showing the five-level power converter according to the second embodiment. As shown in FIG. 2, in the second embodiment, second and third capacitors C2 and C3 are sequentially connected in series between the first positive terminal P1 and the first negative terminal N1, and the first positive terminal P1 and the second positive terminal are connected. A first capacitor C1 is connected between the terminals P2, and a fourth capacitor C4 is connected between the first negative terminal N1 and the second negative terminal N2. In the second embodiment, the charging voltage of the first and fourth capacitors C1 and C4 is E, and the charging voltage of the second and third capacitors C2 and C3 is 2E.

  The switching pattern is the same as in Table 3. Here, the current path in the second embodiment will be described below.

<Output phase voltage VOUT-NP = 2E>
The first and third switching devices S1 and S3 are turned on, the second, fourth to tenth switching devices S2 and S4 to S10 are turned off, and the current is neutral point NP → C2 → S3 → S1 → output terminal It flows through the OUT path. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is 2E. In this switching pattern, the current conducts the two switching devices, the third and first switching devices S3 and S1.

<Output phase voltage VOUT−NP = E>
The first, fourth, and seventh switching devices S1, S4, and S7 are ON, and the second, third, fifth, sixth, and eighth to tenth switching devices S2, S3, S5, S6, and S8 to S10 are ON. Each becomes OFF, and the current flows through the path of neutral point NP → C2 → C1 → S7 → S4 → S1 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is 2E-E = E. In this switching pattern, the current conducts through the three switching devices of the seventh, fourth, and first switching devices S7, S4, and S1.

<Output phase voltage VOUT-NP = 0>
The current path when the output phase voltage VOUT-NP = 0 is the same as in the first embodiment.

<Output phase voltage VOUT-NP = -E>
The second, fifth, and tenth switching devices S2, S5, and S10 are turned on, the first, third, fourth, and sixth to ninth switching devices S1, S3, S4, and S6 to SS9 are turned off. Flows along the path of neutral point NP → C3 → C4 → S10 → S5 → S2 → output terminal OUT. The output phase voltage VOUT−NP between the neutral point NP and the output terminal OUT is −2E + E = −E. In this switching pattern, the current conducts the three switching devices of the tenth, fifth and second switching devices S10, S5 and S2.

<Output phase voltage VOUT-NP = -2E>
The second and sixth switching devices S2 and S6 are each ON, the first, third to fifth, and seventh to tenth switching devices S1, S3 to S5, and S7 to S10 are each OFF, and the current is neutral. It flows through a route of NP → C3 → S6 → S2 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is -2E. In this switching pattern, the current conducts the two switching devices of the sixth and second switching devices S6 and S2.

  Therefore, the same effects as those of the first embodiment are obtained.

[Embodiment 3]
FIG. 3 is a circuit configuration diagram showing a five-level power converter according to the third embodiment. As shown in FIG. 3, in the third embodiment, the first capacitor C1 is connected between the first positive terminal P1 and the neutral point NP, and the second capacitor C2 is connected between the second positive terminal P2 and the neutral point NP. The fourth capacitor C4 is connected between the first negative terminal N1 and the neutral point NP, and the third capacitor C3 is connected between the second negative terminal N2 and the neutral point NP. In the second embodiment, the voltage of the first and fourth capacitors C1 and C4 is 2E, and the voltage of the second and third capacitors C2 and C3 is E. Others are the same as in the first embodiment.

  The switching pattern is the same as in Table 3. Here, the current path in the third embodiment will be described below.

<Output phase voltage VOUT-NP = 2E>
The current path when the output phase voltage VOUT−NP = 2E is the same as that of the second embodiment.

<Output phase voltage VOUT−NP = E>
The current path when the output phase voltage VOUT−NP = E is the same as that of the first embodiment.

<Output phase voltage VOUT-NP = 0>
The current path when the output phase voltage VOUT-NP = 0 is the same as in the first and second embodiments.

<Output phase voltage VOUT-NP = -E>
The current path when the output phase voltage VOUT−NP = −E is the same as the current path of the first embodiment.

<Output phase voltage VOUT-NP = -2E>
The second and sixth switching devices S2 and S6 are each ON, the first, third to fifth, and seventh to tenth switching devices S1, S3 to S5, and S7 to S10 are each OFF, and the current is neutral. It flows through a route of NP → C4 → S6 → S2 → output terminal OUT. The output phase voltage VOUT-NP between the neutral point NP and the output terminal OUT is -2E. In this switching pattern, the current conducts the two switching devices of the sixth and second switching devices S6 and S2.

  Therefore, there exists an effect similar to Embodiment 1,2.

[Embodiment 4]
FIG. 4 is a circuit configuration diagram showing a five-level power converter according to the fourth embodiment. As shown in FIG. 4, the voltage selection circuit 4 in the first embodiment is three-phase connected in parallel to the first to fourth capacitors C1 to C4 in the first embodiment.

  In FIG. 4, the voltage selection circuit 4 is three-phase connected in parallel to the first to fourth capacitors C1 to C4. However, the voltage selection circuit 4 may be connected in two phases in parallel. In FIG. 4, the first to fourth capacitors C1 to C4 and the voltage selection circuit 4 in the first embodiment are applied. However, the first to fourth capacitors C1 to C4 and the voltage selection circuit of the second or third embodiment are applied. 4 may be applied.

  As described above, according to the fourth embodiment, the five-level power conversion device according to the first to third embodiments is connected in a three-phase parallel connection or a two-phase parallel connection, whereby a DC-three-phase AC five-level power conversion is performed. It becomes possible to realize a device or a DC-single-phase AC five-level power converter.

[Embodiment 5]
FIG. 5 is a circuit configuration diagram showing a five-level power converter according to the fifth embodiment. As shown in FIG. 5, six sets of voltage selection circuits 4 in the first embodiment are connected in parallel to the first to fourth capacitors C1 to C4, and the output terminals OUT of the three sets of voltage selection circuits 4 are three-phase AC. By connecting the power supply and the output terminals OUT of the other three sets of voltage selection circuits 4 to a three-phase load, a three-phase AC-three-phase AC power converter can be configured.

  Note that four sets of voltage selection circuits 4 in the first embodiment are connected in parallel to the first to fourth capacitors C1 to C4, and the output terminals OUT of the two sets of voltage selection circuits 4 are connected to a single-phase AC power source. By connecting the output terminals OUT of the other two sets of voltage selection circuits 4 to a single-phase load, a single-phase AC-single-phase AC power converter can be configured.

  In FIG. 5, the first to fourth capacitors C1 to C4 and the voltage selection circuit 4 in the first embodiment are applied. However, the first to fourth capacitors C1 to C4 and the voltage selection circuit of the second or third embodiment are applied. 4 may be applied.

[Embodiment 6]
FIG. 6 is a circuit configuration diagram showing a five-level power converter according to the sixth embodiment. As illustrated in FIG. 6, the five-level power conversion device according to the sixth embodiment has third to tenth switching devices S3 to S10 of the voltage selection circuit with respect to the first to fourth capacitors C1 to C4 according to the fourth embodiment. And a reactor L and a direct-current power supply VDC.

  Specifically, the seventh and eighth switching devices S7 and S8 are connected in series between both terminals of the second capacitor C2, and between the common connection points of the first positive terminal P1 and the seventh and eighth switching devices S7 and S8. The third and fourth switching devices S3 and S4 are sequentially connected in series.

  Further, the ninth and tenth switching devices S9 and S10 are sequentially connected in series between both terminals of the third capacitor C3, and the fifth and sixth switching devices are connected between the ninth and tenth switching devices S9 and S10 and the first negative terminal N1. The switching devices S5 and S6 are sequentially connected in series.

  Further, the reactor L and the DC power supply VDC are connected in series between the common connection point of the third and fourth switching devices S3 and S4 and the common connection point of the fifth and sixth switching devices S5 and S6.

  That is, in the circuit on the left side of the first positive terminal P1, the second positive terminal P2, the neutral point NP, the second negative terminal N2, and the first negative terminal N1, the first and second switching devices S1 and S2 of the first embodiment. Is connected to the reactor L and the DC power supply VDC.

  As described above, in the sixth embodiment, the DC power source VDC is boosted to perform DC-three-phase AC conversion. In other words, a high voltage can be supplied to the three-phase AC load 1.

  In addition, it can apply also to the power converter device which connects a three-phase alternating current power supply instead of the three-phase alternating current load 1 in FIG. 6, and charges / discharges direct current power supply VDC.

  In FIG. 6, the first to fourth capacitors C1 to C4, the voltage selection circuit 4, and the third to tenth switching devices S3 to S10 in the first embodiment are applied, but the first of the second or third embodiment. The fourth capacitors C1 to C4 and the voltage selection circuit 4, and the third to tenth switching devices S3 to S10 may be applied. Moreover, it is good also as a DC-single-phase alternating current 5 level power converter device by making the voltage selection circuit 4 into 2 sets.

[Embodiment 7]
FIG. 7 is a circuit configuration diagram showing a five-level power converter according to the seventh embodiment. The five-level power converter according to the seventh embodiment is different from the first to fourth capacitors C1 to C4 of the AC-AC power converter according to the fifth embodiment with the third to tenth switching devices S3 to S10 according to the sixth embodiment. , A reactor L and a DC power source VDC are provided.

According to the seventh embodiment, (1) when the three-phase AC power source 3 is normal, the three-phase AC power source 3 supplies power to the three-phase AC load 1 through the power converter device and charges the DC power source VDC. .
(2) On the other hand, at the time of a power failure of the three-phase AC power source 3, it has a function of supplying power to the three-phase AC load 1 from the DC power source VDC via the five-level power converter.

  Further, the five-level power conversion device according to the seventh embodiment can be applied to a power conditioner, a UPS, and the like.

[Embodiment 8]
FIG. 8 is a circuit configuration diagram showing a five-level power converter according to the eighth embodiment. The five-level power converter in the eighth embodiment is obtained by replacing the eighth switching device S8 in the first embodiment with a diode D1, and replacing the ninth switching device S9 with a diode D2.

  Table 4 shows switch patterns in the eighth embodiment.

  When the applied voltage of the capacitors C1 to C4 is E, the output voltage to the output terminal OUT with respect to the neutral point NP is set to 5 levels of 2E, E, 0, −E, and −2E in five modes. can do.

  Since the switching patterns of Modes 1, 2, 4, 5 (output phase voltage VOUT-NP = 2E, E, 0, -E, -2E) are the same as those in the first embodiment, description thereof is omitted here, and Mode 3 ( Only the output phase voltage VOUT-NP = 0) will be described.

<Output phase voltage VOUT-NP = 0>
The first and second switching devices S1 and S2 are each ON, and the third to seventh and tenth switching devices S3 to S7 and S10 are each OFF.

(1) When the current is positive The current flows along the path of the neutral point NP → D1 → S4 flywheel diode → S1 → output terminal OUT.

(2) When the current is negative The current flows through the path of the output terminal OUT → S2 → S5 flywheel diode → D2 → neutral point NP.

  As described above, the eighth embodiment has the same operational effects as the first embodiment.

  In the first embodiment, the number of switching elements per phase is ten. In the eighth embodiment, since there are eight switching devices and two diodes, the number of gate driving circuits for driving the switching devices can be reduced.

  Furthermore, since the number of conductions of the switching device is two at any switching pattern, conduction loss can be reduced.

[Embodiment 9]
FIG. 9 is a circuit configuration diagram showing a five-level power converter according to the ninth embodiment. As shown in FIG. 9, the voltage selection circuit 4 in the eighth embodiment is three-phase connected in parallel to the first to fourth capacitors C1 to C4 in the ninth embodiment.

  In FIG. 9, the voltage selection circuit 4 is three-phase connected in parallel to the first to fourth capacitors C1 to C4. However, the voltage selection circuit 4 may be connected in two phases in parallel.

  As described above, according to the ninth embodiment, the five-level power converter according to the eighth embodiment is connected in a three-phase parallel connection or in a two-phase parallel connection, whereby a DC-three-phase AC five-level power converter, Or it becomes possible to implement | achieve a DC-single-phase alternating current 5 level power converter.

  In addition, when the voltage selection circuit 4 is connected in parallel in three phases, it becomes possible to configure a five-level power conversion device from 24 switching elements, 6 diodes, and 4 divided capacitors. The device can be miniaturized.

[Embodiment 10]
FIG. 10 is a circuit configuration diagram showing the five-level power conversion device according to the tenth embodiment. As shown in FIG. 10, six sets of voltage selection circuits 4 in the eighth embodiment are connected in parallel to the first to fourth capacitors C1 to C4, and the output terminals OUT of the three sets of voltage selection circuits 4 are three-phase AC. By connecting the power supply and the output terminals OUT of the other three sets of voltage selection circuits 4 to a three-phase load, a three-phase AC-three-phase AC power converter can be configured.

  Note that four sets of voltage selection circuits 4 in the eighth embodiment are connected in parallel to the first to fourth capacitors C1 to C4, and the output terminals OUT of the two sets of voltage selection circuits 4 are connected to a single-phase AC power source. By connecting the output terminals OUT of the other two sets of voltage selection circuits 4 to a single-phase load, a single-phase AC-single-phase AC power converter can be configured.

  Further, when the voltage selection circuit 4 is connected in three-phase parallel, a five-level power conversion device can be configured from 48 switching elements, 12 diodes, and four divided capacitors.

[Embodiment 11]
The switching elements S8 and S9 on the inverter circuit side of the five-level power converter in the sixth embodiment (FIG. 6) can be replaced with diodes D1 and D2 as in the eighth embodiment.

  Note that the switching elements S8 and S9 on the chopper circuit side cannot be replaced with diodes.

  As a result, the number of switching elements can be reduced as in the eighth embodiment.

[Embodiment 12]
Switching elements S8 and S9 on the inverter circuit side of the five-level power converter in the seventh embodiment (FIG. 7) can be replaced with diodes D1 and D2 as in the eighth embodiment.

  Note that the switching elements S8 and S9 on the chopper circuit side cannot be replaced with diodes.

  As a result, the number of switching elements can be reduced as in the eighth embodiment.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

C1 to C4 ... Capacitors S1 to S10 ... Switching device 4 ... Voltage selection circuit NP ... Neutral point OUT ... Output terminal P ... Positive electrode end N ... Negative electrode end

Claims (10)

A five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage,
First to fourth capacitors sequentially connected in series between the positive and negative electrodes of a DC voltage source;
Seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor;
Ninth and tenth switching devices sequentially connected in series between both terminals of the third capacitor;
Third and fourth switching devices sequentially connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices;
A common connection point of the ninth and tenth switching devices, and fifth and sixth switching devices sequentially connected in series to the negative terminal of the DC voltage source;
A voltage selection circuit having first and second switching devices sequentially connected in series between a common connection point of the third and fourth switching devices and a common connection point of the fifth and sixth switching devices;
With
5. A five-level power converter, wherein the common connection point of the second and third capacitors is a neutral point, and the common connection point of the first and second switching devices is an output terminal. A five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage,
Second and third capacitors sequentially connected in series between the first positive terminal and the first negative terminal of the DC voltage source;
A first capacitor connected between the first positive terminal and the second positive terminal of the DC voltage source;
A fourth capacitor connected between the first negative terminal and the second negative terminal of the DC voltage source; a seventh capacitor connected in series between the second positive terminal of the DC voltage source and the common connection point of the second and third capacitors; An eighth switching device;
Ninth and tenth switching devices sequentially connected in series between the common connection point of the second and third capacitors and the second negative terminal of the DC voltage source;
Third and fourth switching devices sequentially connected in series between the first positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices;
Fifth and sixth switching devices sequentially connected in series between the common connection point of the ninth and tenth switching devices and the first negative terminal of the DC voltage source;
A voltage selection circuit having first and second switching devices sequentially connected in series between a common connection point of the third and fourth switching devices and a common connection point of the fifth and sixth switching devices;
With
5. A five-level power converter, wherein the common connection point of the second and third capacitors is a neutral point, and the common connection point of the first and second switching devices is an output terminal. A five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage,
First and fourth capacitors sequentially connected in series between a first positive terminal and a first negative terminal of a DC voltage source;
A second capacitor connected between the second positive terminal of the DC voltage source and the common connection point of the first and fourth capacitors;
A third capacitor connected between the common connection point of the first and fourth capacitors and the second negative terminal of the DC voltage source;
Seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor;
Ninth and tenth switching devices sequentially connected in series between both terminals of the third capacitor;
Third and fourth switching devices sequentially connected in series between the first positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices;
Fifth and sixth switching devices sequentially connected in series between the common connection point of the ninth and tenth switching devices and the first negative terminal of the DC voltage source;
A voltage selection circuit having first and second switching devices sequentially connected in series between a common connection point of the third and fourth switching devices and a common connection point of the fifth and sixth switching devices. ,
5. A five-level power converter, wherein the common connection point of the second and third capacitors is a neutral point, and the common connection point of the first and second switching devices is an output terminal. A five-level power converter that performs voltage conversion from DC voltage to AC voltage, or voltage conversion from AC voltage to DC voltage,
First to fourth capacitors sequentially connected in series between the positive and negative electrodes of a DC voltage source;
A seventh switching device, a first diode sequentially connected in series between both terminals of the second capacitor;
A second diode, a tenth switching device connected in series between both terminals of the third capacitor;
A third and a fourth switching device sequentially connected in series between the positive terminal of the DC voltage source and the seventh switching device and the common connection point of the first diode;
A common connection point of the second diode and the tenth switching device, and fifth and sixth switching devices sequentially connected in series to the negative terminal of the DC voltage source;
A voltage selection circuit having first and second switching devices sequentially connected in series between a common connection point of the third and fourth switching devices and a common connection point of the fifth and sixth switching devices;
With
5. A five-level power converter, wherein the common connection point of the second and third capacitors is a neutral point, and the common connection point of the first and second switching devices is an output terminal.   5. The five-level power converter according to claim 1, wherein the voltage selection circuit is three-phase connected in parallel to the first to fourth capacitors to obtain a three-phase AC output. .   5. The five-level power converter according to claim 1, wherein the voltage selection circuit is connected in two phases in parallel to the first to fourth capacitors to form a single-phase AC output. . 6. The five-level power conversion according to claim 5, wherein a voltage selection circuit is further added in three phases in parallel to the first to fourth capacitors to form a three-phase AC-three-phase AC conversion. apparatus. 7. The five-level power conversion according to claim 6 , wherein two or more voltage selection circuits are added in parallel to the first to fourth capacitors and connected in parallel to achieve single-phase AC-single-phase AC conversion. apparatus. Seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor with respect to the first to fourth capacitors;
Ninth and tenth switching devices sequentially connected in series between both terminals of the third capacitor;
Third and fourth switching devices sequentially connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices;
Connecting the common connection point of the ninth and tenth switching devices and the fifth and sixth switching devices sequentially connected in series to the negative terminal of the DC voltage source;
7. A reactor and a DC power source are connected in series between a common connection point of the added third and fourth switching devices and a common connection point of the fifth and sixth switching devices. 5 level power converter. Seventh and eighth switching devices sequentially connected in series between both terminals of the second capacitor with respect to the first to fourth capacitors;
Ninth and tenth switching devices sequentially connected in series between both terminals of the third capacitor;
Third and fourth switching devices sequentially connected in series between the positive terminal of the DC voltage source and the common connection point of the seventh and eighth switching devices;
Connecting the common connection point of the ninth and tenth switching devices and the fifth and sixth switching devices sequentially connected in series to the negative terminal of the DC voltage source;
9. A reactor and a DC power source are connected in series between a common connection point of the added third and fourth switching devices and a common connection point of the fifth and sixth switching devices. 5 level power converter.

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