JP2014166119A - Power conversion circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion circuit for further improving power conversion efficiency.SOLUTION: A power conversion circuit 10 includes: a unit circuit comprising a first terminal 102, second terminal 104, first switch element 106, second switch element 108, first rectifier element 110, second rectifier element 112, third switch element 114, fourth switch element 116, third terminal 118, first reactor 120, and LC circuit 122; and a first capacitor 124 and second capacitor 126 connected between the first terminal 102 and second terminal 104. The LC circuit 122 is arranged between a connection point between the first switch element 106 and first rectifier element 110, and the third terminal 118. A point between the first capacitor 124 and second capacitor 126 is connected to a point between the first rectifier element 110 and second rectifier element 112, and is not directly connected to the LC circuit 122.

Description

  The present invention relates to a power conversion circuit that converts alternating current and direct current bidirectionally.

  Power conversion that converts DC power supplied from storage batteries or solar power generation panels into AC power and supplies it to commercial power supplies, or converts AC power supplied from commercial power supplies into DC power and stores it in storage batteries, etc. The vessel is widespread. In such a power converter, some power loss occurs when converting power. Therefore, a power converter having as high a power conversion efficiency as possible is required.

  Patent Document 1 discloses an example of a power conversion circuit that converts input DC power into AC power.

European Patent Application Publication No. 2421135

  In the power conversion circuit described in Patent Document 1, the midpoint of two capacitors arranged in series on the output side is connected to the DC bus on the input side. For this reason, when AC power is output, it appears that the output-side capacitor and the reactor are connected in parallel. As a result, the current from the midpoint of the rectifying element is divided into a current flowing through the reactor and a current flowing through the capacitor. As a result, in the power conversion circuit described in Patent Document 1, the capacitor and the reactor do not function as an original LC filter, thereby degrading the power conversion efficiency.

  In view of the above problems, an object of the present invention is to provide a power conversion circuit that further improves power conversion efficiency.

According to the present invention,
A first terminal connected to the positive terminal of the DC power supply;
A second terminal connected to the negative terminal of the DC power supply;
A first switch element having one end connected to the first terminal;
A second switch element having one end connected to the second terminal;
First and second rectifier elements connected in series in the same direction and connected between the other end of the first switch element and the other end of the second switch element;
Third and fourth switch elements connected in series to each other and connected in parallel to the first and second rectifying elements;
A third terminal connected to an AC power source;
A first reactor having one end connected between the third and fourth switch elements and the other end connected to the third terminal;
An LC circuit disposed between a connection point between the other end of the first switch element and the first rectifier element, and the third terminal;
A unit circuit comprising:
First and second capacitors connected in series with each other and connected between the first and second terminals;
Have
The first and second capacitors are connected between the first and second rectifier elements and are not directly connected to the LC circuit.
A power conversion circuit is provided.

  According to the present invention, the efficiency during power conversion can be improved.

It is a figure which shows the structural example of the power converter circuit in 1st Embodiment. It is a figure for demonstrating the state of the power converter circuit which changes by switching a 1st switch element and a 2nd switch element. It is a figure for demonstrating the flow which a power converter circuit produces | generates a half wave by switching a 1st switch element and a 2nd switch element. It is a figure which shows the structure of the power converter circuit in the modification of 1st Embodiment. It is a figure which shows the structure of the power converter circuit of 2nd Embodiment. It is a figure which shows the structure of the power converter circuit in the 1st modification of 2nd Embodiment. It is a figure which shows the structure of the power converter circuit 10 in the 2nd modification of 2nd Embodiment. It is a figure which shows the structure of the power converter circuit when the 1st and 2nd modification of 2nd Embodiment is match | combined. It is a figure which shows the structure of the power converter circuit in 3rd Embodiment. It is a figure which shows the structure of the unit circuit used for the power converter circuit in 3rd Embodiment. It is a figure which shows the structure of the power converter circuit in the modification of 3rd Embodiment. It is a figure which shows the structure of the unit circuit used for the power converter circuit in the modification of 3rd Embodiment. It is a figure which shows the structural example of the power converter circuit which converts electric power bidirectionally. It is a figure which shows the structural example of the power converter circuit connected to a single phase alternating current power supply and converting electric power bidirectionally. It is a figure for demonstrating the method to convert alternating current power into direct-current power.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a power conversion circuit 10 according to the first embodiment. The power conversion circuit 10 includes a first terminal 102, a second terminal 104, a first switch element 106, a second switch element 108, a first rectifier element 110, a second rectifier element 112, a third switch element 114, and a fourth switch element. 116, a third terminal 118, a first reactor 120, and a unit circuit including an LC circuit 122, a first capacitor 124, and a second capacitor 126. As the first to fourth switch elements 106, 108, 114, 116, for example, bipolar transistors, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), or the like can be used.

  The first terminal 102 is connected to a positive terminal of a DC power source (not shown). The second terminal 104 is connected to the negative terminal of the DC power supply. One end of the first switch element 106 is connected to the first terminal 102, and one end of the second switch element 108 is connected to the second terminal 104. The first rectifying element 110 and the second rectifying element 112 are connected in series with each other. The first rectifier element 110 and the second rectifier element 112 are connected between the other end of the first switch element 106 and the other end of the second switch element 108. The first rectifier element 110 is connected to the other end of the first switch element 106, and the second rectifier element 112 is connected to the other end of the second switch element 108. The third switch element 114 and the fourth switch element 116 are connected in series with each other. The third switch element 114 and the fourth switch element 116 are connected in parallel to the first rectifier element 110 and the second rectifier element 112. The third terminal 118 is connected to an AC power source (not shown). One end of the first reactor 120 is connected between the third switch element 114 and the fourth switch element 116. The other end of the first reactor 120 is connected to the third terminal 118.

  The LC circuit 122 is disposed between the connection point between the first switch element 106 and the first rectifying element 110 and the third terminal 118. FIG. 1 shows an example in which the first rectifying element 110 and the second rectifying element 112 are arranged between the third switch element 114 and the fourth switch element 116. In FIG. 1, the LC circuit 122 includes a second reactor 128 and a third capacitor 130. In FIG. 1, one end of the second reactor 128 is connected between the first switch element 106 and the first rectifier element 110. Further, one end of the third capacitor 130 is connected between the second switch element 108 and the second rectifying element 112, and the other end is connected to the other end of the second reactor 128.

  As shown in FIG. 1, the midpoint of the first capacitor 124 and the second capacitor 126 arranged on the input side is not directly connected to the LC circuit 122. Thus, the LC circuit 122 can function as an original LC filter, and can prevent deterioration in power conversion efficiency.

Next, the operation of the power conversion circuit 10 will be described. Assuming that the voltage of the DC power supply is V _in [V], the input voltage is divided into V _in / 2 [V] by the first capacitor 124 and the second capacitor 126 as shown _in FIG. As a result, the power conversion circuit 10 can generate three levels of voltages V _in [V], V _in / 2 [V], and 0 [V]. Specifically, the power conversion circuit 10 uses the three levels of voltages by switching the ON / OFF states of the first switch element 106 and the second switch element 108 as shown in FIG. FIG. 2 is a diagram for explaining the state of the power conversion circuit 10 that changes by switching the first switch element 106 and the second switch element 108. FIG. 2A shows a case where both the first switch element 106 and the second switch element 108 are in the ON state. In this case, the input voltage is V _in [V]. FIG. 2B shows a case where both the first switch element 106 and the second switch element 108 are in the OFF state. In this case, the input voltage is 0 [V]. FIG. 2C shows a case where only the second switch element 108 is in the ON state. In this case, the input voltage is V _in / 2 [V]. FIG. 2D shows a case where only the first switch element 106 is in an ON state. In this case, the input voltage is V _in / 2 [V].

FIG. 3 is a diagram for explaining a flow in which the power conversion circuit 10 generates a half wave by switching the first switch element 106 and the second switch element 108. The power conversion circuit 10 switches each state shown in FIGS. 2A to 2D depending on whether or not the instantaneous value of the generated half-wave voltage is larger than V _in / 2 [V].

Specifically, in the region where the instantaneous value of the half-wave voltage shown in region (a) of FIG. 3 is equal to or less than V _in / 2 [V], the power conversion circuit 10 operates as shown in FIGS. C) or between FIG. 2 (B) and FIG. 2 (D). When switching between FIG. 2B and FIG. 2C, the charge accumulated in the second capacitor 126 is released. When switching between FIG. 2B and FIG. 2D, the charge accumulated in the first capacitor 124 is released. In addition, the power conversion circuit 10 adjusts the length of time in which the state shown in FIG. 2C or FIG. 2D is set and the length of time in which the state shown in FIG. A PWM (Pulse Width Modulation) signal corresponding to a value of 0 [V] to V _in / 2 [V] is generated. Using this PWM signal, a half wave in the region (a) is generated.

Further, in the region shown in the region (b) of FIG. 3 where the instantaneous value of the half-wave voltage exceeds V _in / 2 [V], the power conversion circuit 10 operates as shown in FIGS. 2 (A) and 2 (C). Or between FIG. 2 (A) and FIG. 2 (D). When switching between FIG. 2A and FIG. 2C, the charge accumulated in the second capacitor 126 is released. When switching between FIG. 2A and FIG. 2D, the charge accumulated in the first capacitor 124 is released. Further, the power conversion circuit 10 adjusts the length of time in which the state shown in FIG. 2C or FIG. 2D is set and the length of time in which the state shown in FIG. A PWM signal whose value corresponds to a portion of V _in / 2 [V] to V _in [V] is generated. Using this PWM signal, a half wave in the region (b) is generated.

  Here, if only one of the first capacitor 124 and the second capacitor 126 is continuously used, the voltage balance between the first capacitor 124 and the second capacitor 126 is lost. Specifically, since the first capacitor 124 and the second capacitor 126 divide the input voltage, when the charge accumulated in one capacitor is released and the voltage decreases, the voltage of the other capacitor is reduced. Becomes higher. This voltage imbalance causes the output waveform to be distorted. Therefore, the power conversion circuit 10 performs control so that the voltage balance between the first capacitor 124 and the second capacitor 126 is not excessively broken. For example, the power conversion circuit 10 monitors the voltages of the first capacitor 124 and the second capacitor 126, and when the voltage of the currently used capacitor becomes equal to or lower than a predetermined threshold voltage, the power conversion circuit 10 Control to switch to the capacitor. This threshold voltage is set to an appropriate value in consideration of the characteristics of the first capacitor 124 and the second capacitor 126.

  The power conversion circuit 10 uses the third switch element 114 and the fourth switch element 116 to generate a sine wave by partially inverting the polarity of the half wave. For example, the sine wave generated here is output via the third terminal 118 as AC power. The first reactor 120 plays a role of separating the voltage output from the AC power supply and the voltage output from the power conversion circuit 10. The power conversion circuit 10 measures the voltage output from the power conversion circuit 10 and the voltage of the AC power supply via the first reactor 120, respectively, and adjusts the phase of the voltage output from the power conversion circuit 10. Thus, the electric power converted into the AC power source can be supplied.

  As described above, according to the present embodiment, the midpoints of the first capacitor 124 and the second capacitor 126 arranged on the input side are not directly connected to the LC circuit 122, and the first switch element 106 and the second switch element 108 are connected. No matter how the switching is performed, the LC circuit 122 is not directly connected. Thereby, it can prevent that power conversion efficiency deteriorates. Here, the efficiency at the time of outputting 10 kW (DC: 400 V, AC: 200 V) was 97.7% in the conventional method described in Patent Document 1. On the other hand, it was confirmed that the efficiency was 98.1% in the new method using the power conversion circuit 10 of the present embodiment under the same conditions. If this new system is adopted in a system that handles megawatt-class power such as mega solar, for example, the parameter of the power to be handled becomes large, so that a more remarkable effect can be expected.

(Modification of the first embodiment)
The LC circuit 122 can be arranged at a position as shown in FIG. 4, for example. FIG. 4 is a diagram illustrating a configuration of the power conversion circuit 10 according to a modification of the first embodiment.

  In FIG. 4, the LC circuit 122 is disposed between the connection point of the third switch element 114 and the fourth switch element 116 and the third terminal 118. In FIG. 4, the LC circuit 122 includes a first reactor 120 and a third capacitor 130. In FIG. 4, the first reactor 120 also serves as the second reactor 128 shown in FIG. 1, and functions as an LC filter together with the third capacitor 130.

  As described above, also in this modified example, the reactor and the capacitor constituting the LC circuit 122 do not appear to be connected in parallel, and the same effect as in the first embodiment can be obtained. Moreover, according to this modification, since the number of reactors is smaller than that of the power conversion circuit 10 shown in FIG. 1, the conduction loss due to the reactor can be reduced, and the power conversion efficiency can be further improved.

(Second Embodiment)
This embodiment is the same as the first embodiment except for the following points.

  FIG. 5 is a diagram illustrating a configuration of the power conversion circuit 10 according to the second embodiment. In FIG. 5, the power conversion circuit 10 further includes a fifth switch element 132, a sixth switch element 134, and a fourth terminal 136. With this configuration, the power conversion circuit 10 according to the present embodiment can supply AC power converted from DC power to a single-phase AC power supply. As the fifth switch element 132 and the sixth switch element 134, bipolar transistors, MOSFETs, and the like can be used as in the first to fourth switch elements 106, 108, 114, and 116.

  The fifth switch element 132 and the sixth switch element 134 are connected in series with each other. The fifth switch element 132 and the sixth switch element 134 are connected in parallel with the first rectifier element 110 and the second rectifier element 112, and the third switch element 114 and the fourth switch element 116. The fourth terminal 136 is connected between the fifth switch element 132 and the sixth switch element 134. The fourth terminal 136 is connected to a single-phase AC power source (not shown) together with the third terminal 118.

  In the power conversion circuit 10 according to the present embodiment, the polarity of part of the half wave generated in the same manner as in the first embodiment is inverted by the first to fourth switch elements 106, 108, 132, and 134, and the sine wave is generated. Generated. Specifically, when the polarity of the half wave is reversed, the third switch element 114 and the sixth switch element 134 are turned off, and the fourth switch element 116 and the fifth switch element 132 are turned on. When the half wave polarity is not reversed, the third switch element 114 and the sixth switch element 134 are turned on, and the fourth switch element 116 and the fifth switch element 132 are turned off. A sine wave is generated by performing this operation on every other half wave generated.

  As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, according to the present embodiment, AC power converted from DC power using the configuration of the first embodiment can be supplied to the single-phase AC power supply.

(First Modification of Second Embodiment)
Also in the present embodiment, the arrangement of the LC circuit 122 can be changed as in the first embodiment. The LC circuit 122 can be arranged at a position as shown in FIG. 6, for example. FIG. 6 is a diagram illustrating a configuration of the power conversion circuit 10 according to a first modification of the second embodiment. In FIG. 6, the other end of the third capacitor 130 is connected between the connection point of the fifth switch element 132 and the sixth switch element 134 and the fourth terminal 136.

  Also in this modification, the effect similar to the effect demonstrated in the modification of 1st Embodiment can be acquired.

(Second Modification of Second Embodiment)
Considering the path of the entire apparatus to which the power conversion circuit 10 is applied, the power conversion circuit 10 can be configured as shown in FIG. FIG. 7 is a diagram illustrating a configuration of the power conversion circuit 10 according to a second modification of the second embodiment.

  In FIG. 7, the power conversion circuit 10 further includes a third reactor 138. Here, the current output from the third terminal 118 via the first reactor 120 returns to the fourth terminal 136 via an AC load (not shown) and passes through the third reactor 138. That is, the same effect can be obtained as long as the combined reactance value of the first reactor 120 and the third reactor 138 is the same as the reactance value of the first reactor in FIG.

  As described above, also in this modification, the same effect as that of the second embodiment can be obtained. Further, by further providing the third reactor 138, it can function as a common mode filter that removes the common mode, and the noise quality of the apparatus can be improved.

  Moreover, the 1st modification of 2nd Embodiment is applied to this modification, and the power converter circuit 10 can also be set as a structure like FIG. FIG. 8 is a diagram illustrating a configuration of the power conversion circuit 10 when the first and second modifications of the second embodiment are combined. If it does in this way, the effect which put together the 1st and 2nd modification of 2nd Embodiment can be acquired.

(Third embodiment)
This embodiment is the same as the first embodiment except for the following points.

  FIG. 9 is a diagram illustrating a configuration of the power conversion circuit 10 according to the third embodiment. In FIG. 9, the power conversion circuit 10 has three unit circuits 100U, 100V, and 100W. Each unit circuit 100U, 100V, and 100W is the same as the unit circuit arrange | positioned in the power converter circuit 10 demonstrated in FIG. 1 of 1st Embodiment. FIG. 10 is a diagram illustrating a configuration of the unit circuit 100 used in the power conversion circuit 10 according to the third embodiment. In FIG. 10, the unit circuits 100U, 100V, and 100W have a positive DC terminal 140, a negative DC terminal 142, an AC terminal 144, and an intermediate terminal 146.

  In FIG. 9, the positive DC terminals 140 of the unit circuits 100 </ b> U, 100 </ b> V, and 100 </ b> W are connected to the first terminal 102. The negative DC terminals 142 of the unit circuits 100U, 100V, and 100W are connected to the second terminal 104. The AC terminals 144 of the unit circuits 100U, 100V, and 100W are connected to a three-phase AC power source (not shown). One of the unit circuits 100U, 100V, and 100W outputs a first phase voltage via the AC terminal 144. The other one of the unit circuits 100U, 100V, and 100W outputs a second-phase voltage via the AC terminal 144. The last one of the unit circuits 100U, 100V, and 100W outputs a third-phase voltage via the AC terminal 144. Of the unit circuits 100U, 100V, and 100W, the combination of the unit circuits 100U, 100V, and 100W with which phase voltage is output is arbitrary and is not particularly limited. The intermediate terminals 146 of the unit circuits 100U, 100V, and 100W are connected between the first capacitor 124 and the second capacitor 126. Thereby, in each of unit circuit 100U, 100V, and 100W, between the 1st capacitor 124 and the 2nd capacitor 126 and between the 1st switch element 106 and the 2nd switch element 108 are connected.

  In the power conversion circuit 10 according to the present embodiment, each unit circuit 100U, 100V, and 100W generates a sine wave as described in the first embodiment, and the sine wave is output via each AC terminal 144. . Here, among the unit circuits 100U, 100V, and 100W, in the unit circuit that outputs the voltage of the first phase, a half wave is generated as in the first embodiment, and a sine wave is generated from the half wave. Of the unit circuits 100U, 100V, and 100W, the unit circuit that outputs the voltage of the second phase generates a half wave that is 120 degrees out of phase with the half wave generated in the first phase. A sine wave is generated from the wave. The unit circuit that outputs the second phase voltage shifts the timing of switching the ON / OFF state of the first switch element 106 and the second switch element 108 with respect to the unit circuit that outputs the first phase voltage, A rectangular wave whose phase is shifted by 120 degrees can be generated. The unit circuit that outputs the voltage of the second phase generates a half wave whose phase is shifted by 120 degrees using a rectangular wave whose phase is shifted by 120 degrees. Of the unit circuits 100U, 100V, and 100W, the unit circuit that outputs the voltage of the third phase generates a half wave whose phase is shifted by 240 degrees with respect to the half wave generated in the first phase. A sine wave is generated from the wave. Similar to the unit circuit that outputs the second phase voltage, the unit circuit that outputs the third phase voltage generates a rectangular wave that is 240 degrees out of phase, and a half wave that is 240 degrees out of phase from the rectangular wave. Is generated.

  As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, according to this embodiment, it can be applied to the case of using three-phase AC power.

(Modification of the third embodiment)
As a modification of the third embodiment, the unit circuit described in the modification of the first embodiment can also be used. FIG. 11 is a diagram illustrating a configuration of the power conversion circuit 10 according to a modification of the third embodiment.

  In FIG. 11, the power conversion circuit 10 includes three unit circuits 100U ′, 100V ′, and 100W ′. Each unit circuit 100U ', 100V', and 100W 'is the same as the unit circuit arrange | positioned in the power converter circuit 10 demonstrated in FIG. 4 of 1st Embodiment. In FIG. 11, the other ends of the third capacitors 130 of the unit circuits 100U ′, 100V ′, and 100W ′ are connected to each other. FIG. 12 is a diagram illustrating a configuration of a unit circuit 100 ′ used in the power conversion circuit 10 according to a modification of the third embodiment. In FIG. 12, unit circuits 100U ′, 100V ′, and 100W ′ have a positive DC terminal 140, a negative DC terminal 142, an AC terminal 144, and an intermediate terminal 146, similarly to the unit circuit 100 shown in FIG.

  In FIG. 12, the positive DC terminals 140 of the unit circuits 100U ′, 100V ′, and 100W ′ are connected to the first terminal 102. The negative DC terminals 142 of the unit circuits 100U ′, 100V ′, and 100W ′ are connected to the second terminal 104. The AC terminals 144 of the unit circuits 100U ′, 100V ′, and 100W ′ are connected to a three-phase AC power source (not shown). One of the unit circuits 100U ′, 100V ′, and 100W ′ outputs a first-phase voltage via the AC terminal 144. In addition, the other one of 100U ′, 100V ′, and 100W ′ outputs the voltage of the second phase via the AC terminal 144. The last one of the unit circuits 100U ′, 100V ′, and 100W ′ outputs a third-phase voltage via the AC terminal 144. Of the unit circuits 100U ′, 100V ′, and 100W ′, which unit circuit outputs the voltage of which phase is arbitrary and is not particularly limited. The intermediate terminals 146 of the unit circuits 100U ′, 100V ′, and 100W ′ are connected between the first capacitor 124 and the second capacitor 126. Thereby, in each of unit circuit 100U ', 100V', and 100W ', between the 1st capacitor 124 and the 2nd capacitor 126 and between the 1st switch element 106 and the 2nd switch element 108 are connected.

  In the power conversion circuit 10 according to this modification, each unit circuit 100U ′, 100V ′, and 100W ′ generates a sine wave as described in the first embodiment, and the sine wave passes through each AC terminal 144. Is output. Here, among the unit circuits 100U ′, 100V ′, and 100W ′, in the unit circuit that outputs the voltage of the first phase, a half wave is generated as in the first embodiment, and a sine wave is generated from the half wave. Is done. In addition, among the unit circuits 100U ′, 100V ′, and 100W ′, the unit circuit that outputs the voltage of the second phase generates a half wave whose phase is shifted by 120 degrees with respect to the half wave generated in the first phase. A sine wave is generated from the half wave. The unit circuit that outputs the second phase voltage shifts the timing of switching the ON / OFF state of the first switch element 106 and the second switch element 108 with respect to the unit circuit that outputs the first phase voltage, A rectangular wave whose phase is shifted by 120 degrees can be generated. The unit circuit that outputs the voltage of the second phase generates a half wave whose phase is shifted by 120 degrees using a rectangular wave whose phase is shifted by 120 degrees. In addition, among the unit circuits 100U ′, 100V ′, and 100W ′, the unit circuit that outputs the voltage of the third phase generates a half wave whose phase is shifted by 240 degrees with respect to the half wave generated in the first phase. A sine wave is generated from the half wave. Similar to the unit circuit that outputs the second phase voltage, the unit circuit that outputs the third phase voltage generates a rectangular wave that is 240 degrees out of phase, and a half wave that is 240 degrees out of phase from the rectangular wave. Is generated.

  As described above, according to this modification, it is possible to obtain the same effect as that of the first embodiment. Furthermore, according to this modification, it is applicable also when using three-phase alternating current power. Moreover, according to this modification, since the number of reactors is smaller than that of the power conversion circuit 10 shown in FIG. 9, the conduction loss due to the reactor can be reduced, and the power conversion efficiency can be further improved.

  As mentioned above, although embodiment of this invention was described with reference to drawings, each above-mentioned embodiment and each modification can be combined in the range which the content does not conflict. Moreover, these are illustrations of the present invention, and various configurations other than those described above can be employed.

  For example, as shown in FIG. 13, a switch element is connected in parallel to each of the first rectifier element 110 and the second rectifier element 112, and each of the first to fourth switch elements 106, 108, 114, and 116 is connected. Further, the rectifying elements may be connected in parallel. FIG. 13 is a diagram illustrating a configuration example of the power conversion circuit 10 that converts power bidirectionally. By doing in this way, the alternating current power input from alternating current power supply can also be converted into direct current power. When connected to a three-phase AC power source as in the third embodiment, the unit circuit arranged in the power conversion circuit 10 shown in FIG. 13 is replaced with the power conversion circuit 10 shown in FIG. 9 or FIG. Apply.

  Moreover, when connecting to a single phase alternating current power supply, if it is set as a structure like FIG. 14, electric power can be converted bidirectionally. FIG. 14 is a diagram illustrating a configuration example of a power conversion circuit 10 that is connected to a single-phase AC power source and converts power bidirectionally. In FIG. 14, a switch element is connected in parallel to each of the first rectifier element 110 and the second rectifier element 112, and each of the first to sixth switch elements 106, 108, 114, 116, 132, and 134 is Rectifier elements are connected in parallel.

  Here, as an example, a method for converting AC power into DC power using the power conversion circuit 10 shown in FIG. 14C will be described. FIG. 15 is a diagram for explaining a method of converting AC power into DC power.

  The power conversion circuit 10 converts the AC voltage into a DC voltage by repeating the patterns A and B in FIG. In FIG. 14, the third to sixth switch elements 114, 116, 132, and 134 arranged on the AC side function as rectifiers. The AC power input from the AC power source is rectified by the rectifying elements connected in parallel to the third to sixth switch elements 114, 116, 132, and 134, and becomes a half wave. Then, by switching the ON / OFF state of the first switch element 106 and the second switch element 108 by using the half wave generated through the third to sixth switch elements 114, 116, 132, and 134 as an input, A square wave is generated. This rectangular wave is averaged and boosted to generate a DC voltage. Note that the DC voltage step-up ratio is determined in accordance with the ratio of A and the pattern in FIG.

10 power conversion circuit 100U unit circuit 100V unit circuit 100W unit circuit 100U ′ unit circuit 100V ′ unit circuit 100W ′ unit circuit 102 first terminal 104 second terminal 106 first switch element 108 second switch element 110 first rectifier element 112 first 2 rectifier elements 114 3rd switch element 116 4th switch element 118 3rd terminal 120 1st reactor 122 LC circuit 124 1st capacitor 126 2nd capacitor 128 2nd reactor 130 3rd capacitor 132 5th switch element 134 6th switch element 136 Fourth terminal 138 Third reactor 140 Positive DC terminal 142 Negative DC terminal 144 AC terminal 146 Intermediate terminal

Claims (10)

A first terminal connected to the positive terminal of the DC power supply;
A second terminal connected to the negative terminal of the DC power supply;
A first switch element having one end connected to the first terminal;
A second switch element having one end connected to the second terminal;
First and second rectifier elements connected in series in the same direction and connected between the other end of the first switch element and the other end of the second switch element;
Third and fourth switch elements connected in series to each other and connected in parallel to the first and second rectifying elements;
A third terminal connected to an AC power source;
A first reactor having one end connected between the third and fourth switch elements and the other end connected to the third terminal;
An LC circuit disposed between a connection point between the other end of the first switch element and the first rectifier element, and the third terminal;
A unit circuit comprising:
First and second capacitors connected in series with each other and connected between the first and second terminals;
Have
The first and second capacitors are connected between the first and second rectifier elements and are not directly connected to the LC circuit.
Power conversion circuit. The LC circuit
Arranged between the first and second rectifier elements and the third and fourth switch elements;
A second reactor having one end connected between the other end of the first switch element and the first rectifying element;
A third capacitor having one end connected between the other end of the second switch element and the second rectifying element and the other end connected to the other end of the second reactor;
The power conversion circuit according to claim 1. The LC circuit
Between the connection point of the third and fourth switch elements and the third terminal;
The first reactor;
A third capacitor connected at one end between the other end of the first reactor and the third terminal;
The power conversion circuit according to claim 1. Fifth and sixth switch elements connected in series with each other, connected in parallel with the first and second rectifier elements, and the third and fourth switch elements;
A fourth terminal connected between the fifth and sixth switch elements;
Further having
The power conversion circuit according to claim 2. Fifth and sixth switch elements connected in series with each other, connected in parallel with the first and second rectifier elements, and the third and fourth switch elements;
A fourth terminal connected between the fifth and sixth switch elements;
Further comprising
The other end of the third capacitor is connected between a connection point of the fifth and sixth switch elements and the fourth terminal.
The power conversion circuit according to claim 3. A third reactor having one end connected between the fifth and sixth switch elements and the other end connected to the fourth terminal;
The power conversion circuit according to claim 4 or 5. Having three unit circuits,
The three unit circuits are:
Each of the first terminals is connected to a positive terminal of the DC power source,
Each said 2nd terminal is connected to the negative electrode terminal of the said DC power supply,
Each of the third terminals is connected to a three-phase AC power source, one is applied with a first phase voltage, the other is applied with a second phase voltage, and the last is applied with a third phase voltage.
The first and second capacitors are connected between the first and second switch elements of the three unit circuits, respectively.
The power conversion circuit according to claim 2. Having three unit circuits,
The three unit circuits are:
Each of the first terminals is connected to a positive terminal of the DC power source,
Each said 2nd terminal is connected to the negative electrode terminal of the said DC power supply,
Each of the third terminals is connected to a three-phase AC power source, one is applied with a first phase voltage, the other is applied with a second phase voltage, and the last is applied with a third phase voltage.
The other ends of the third capacitors are connected to each other,
The first and second capacitors are connected between the first and second switch elements of the three unit circuits, respectively.
The power conversion circuit according to claim 3. A switch element is connected in parallel to each of the first and second rectifying elements,
A rectifier element is connected in parallel to each of the first to fourth switch elements.
The power conversion circuit according to any one of claims 1 to 3, 7, and 8. A switch element is connected in parallel to each of the first and second rectifying elements,
A rectifier element is connected in parallel to each of the first to sixth switch elements.
The power conversion circuit according to any one of claims 4 to 6.

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