JP2006087212A - Power conversion equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide power conversion equipment wherein ripple currents associated with the switching operation of converter-side and inverter-side switching elements can be effectively reduced and the number of smoothing capacitors of the entire equipment can be reduced for the reduction of cost and size. <P>SOLUTION: The power conversion equipment includes: a first semiconductor switch 21 located on the converter side; a second semiconductor switch 22 located on the inverter side; and a smoothing capacitor 3 that attenuates both ripple currents generated in the semiconductor switches 21 and 22. A first connection line 91 severally connected to the first semiconductor switch 21 and a second connection line 92 severally connected to the second semiconductor switch 22 are connected in common to a connection line 95 connected to the smoothing capacitor 3 to construct one circuit unit 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power conversion device that converts AC power into a desired voltage and frequency.

  In recent years, as a power source for electronic devices, electronic computers, etc., an uninterruptible power supply that keeps the voltage and frequency supplied to the load constant so that it is not affected by the instantaneous voltage drop or power failure that occurs in the power system ( UPS) is used.

  For example, as shown in FIG. 13, such an uninterruptible power supply device includes a power conversion device including a converter CONV and an inverter INV, and a battery B. In normal times, commercial AC power is converted into direct current by the converter CONV. After the conversion to electric power, the inverter INV converts it into alternating current of a predetermined constant voltage and constant frequency and supplies it to the load. At the same time, the battery B is charged with floating charge to compensate for the self-discharge by the direct current power obtained by the converter CONV. Do. When the commercial AC power supply causes a power failure or the like, power is supplied from the battery B to the load via the inverter INV.

  The converter CONV and the inverter INV that constitute the power conversion device described above each include a semiconductor switch such as IGBT or GTO, and a smoothing capacitor. For this reason, in the prior art, a semiconductor switch and a smoothing capacitor are unitized on the converter side and the inverter side, respectively, and the power converter is configured by connecting the two (for example, Patent Document) 1 and 2 etc.).

  FIG. 14 is a circuit diagram showing a simplified connection state of such a power converter. Here, only one phase is shown, and a battery and the like are omitted.

  In the figure, reference numeral 1a denotes a circuit unit on the converter side, which includes a semiconductor switch 2a that rectifies an AC power supply and a smoothing capacitor 3a that attenuates a ripple current generated by the switching operation of the semiconductor switch 2a. Reference numeral 1b denotes a circuit unit on the inverter side, which includes a semiconductor switch 2b that chops DC power and converts it into AC of constant voltage and constant frequency, and a smoothing capacitor 3b that attenuates ripple current generated by the switching operation of the semiconductor switch 2b. Prepare. The circuit units 1 a and 1 b are connected to each other via a connection line 9. In the case of AC three-phase, three circuit units 1a and 1b on the converter side and the inverter side are respectively connected in parallel.

  Further, as shown in FIGS. 15 and 16, in one circuit unit 1a, a cooling fin 4a is provided for the semiconductor switch 2a, and the semiconductor switch 2a, the cooling fin 4a, and the smoothing capacitor 3a are not shown in the frame. It is attached integrally. Similarly, the other circuit unit 1b is provided with a cooling fin 4b for the semiconductor switch 2b, and the semiconductor switch 2b, the cooling fin 4b, and the smoothing capacitor 3b are integrally attached to a frame (not shown). 15 and 16 show a case where the smoothing capacitors 3a and 3b of the circuit units 1a and 1b shown in FIG. 14 are each composed of three capacitors.

  Each circuit unit 1a, 1b is housed in parallel in a housing 5 for housing equipment, and a cooling fan 6 is provided on the top of the housing 5 and further provided in the housing 5. The sheet metal 71 and 72 guides the flow of wind from the lower front surface of the housing 5 to the upper rear side of the housing 5.

  In the power converter having the above configuration, in the circuit unit 1a on the converter side, the AC power source is rectified by the semiconductor switch 2a, and the ripple current generated by the switching operation of the semiconductor switch 2a is smoothed by the nearest smoothing capacitor 3a. The Further, in the circuit unit 1b on the inverter side, the DC power is chopped by the semiconductor switch 2b and converted into AC of constant voltage and constant frequency, and the ripple current generated by the switching operation of the semiconductor switch 2b is caused by the nearest smoothing capacitor 3b. Attenuated.

  At that time, wind is generated by starting the cooling fan 6, and this wind is sucked from the lower front surface of the housing 5 as indicated by the broken line in FIG. 3a and 3b and cooling fins 4a and 4b are passed. Thereby, the temperature rise by the loss of smoothing capacitor 3a, 3b and semiconductor switch 2a, 2b is suppressed. Then, the wind is guided to the upper rear side of the housing 5 by the metal plates 71 and 72 and is discharged to the outside of the housing 5 through the cooling fan 6.

Japanese Patent Laid-Open No. 8-140363 Japanese Patent Laid-Open No. 11-220887

  In the meantime, in the conventional configuration shown in FIGS. 14 to 16, the circuit units 1a and 1b on the converter side and the inverter side are independent, and both 1a and 1b are connected to each other via a connection line 9. Yes. Therefore, the length of the connection line 9 connecting the two circuit units 1a and 1b is inevitably long, and it is necessary to provide the smoothing capacitors 3a and 3b for each circuit unit 1a and 1b.

  That is, since the ripple current generated in each of the semiconductor switches 2a and 2b has a high frequency, it is necessary to flow through the smoothing capacitor via a wiring path having a small inductance. That is, smoothing capacitors 3a and 3b are individually provided close to each semiconductor switch 2a and 2b, and the ripple current generated in one semiconductor switch 2a is the nearest smoothing capacitor 3a, and the ripple current generated in the other semiconductor switch 2b is the nearest. Attenuate by the smoothing capacitor 3b.

  As described above, since the circuit unit 1a and 1b are configured on the converter side and the inverter side, respectively, it is necessary to provide the smoothing capacitors 3a and 3b individually for each circuit unit 1a and 1b. For this reason, the number of capacitors in the entire apparatus has increased. As a result, it is difficult not only to increase the cost but also to reduce the size of the apparatus.

  The present invention has been made to solve the above-described problems, and not only can the ripple current associated with the switching operation of each switching element on the converter side and the inverter side be effectively reduced, but also the number of smoothing capacitors in the entire apparatus can be reduced. Then, it aims at providing the power converter device which can achieve cost reduction and size reduction of an apparatus.

  In order to achieve the above object, a power conversion device of the present invention includes a first semiconductor switch on a converter side that converts AC power into DC power, and a second semiconductor switch on an inverter side that converts DC power into desired AC power. And a smoothing capacitor that attenuates both ripple currents generated in both semiconductor switches, and a first connection line individually connected to the first semiconductor switch and a second connection individually connected to the second semiconductor switch. One circuit unit is configured by connecting the line in common to the connection line connected to the smoothing capacitor.

  According to the present invention, since the first and second semiconductor switches and the smoothing capacitor are configured as one circuit unit as a whole, the distance between the first and second semiconductor switches connected to the smoothing capacitor is shortened. For this reason, the high-frequency ripple current generated in each semiconductor switch has a small inductance due to the short distance between the connections, and thus can be sufficiently attenuated by a smoothing capacitor connected in common to both semiconductor switches. In addition, since the first and second semiconductor switches are connected in common to the smoothing capacitor, the ripple current generated in each semiconductor switch is offset. As a result, not only can the ripple current associated with the switching operation of the switching elements on the converter side and the inverter side be effectively reduced, but the number of smoothing capacitors in the entire apparatus can be reduced, thereby reducing costs and downsizing the apparatus. It becomes possible.

Embodiment 1 FIG.
1 is a circuit diagram showing a simplified connection state of a circuit unit of a power conversion device according to Embodiment 1 of the present invention, and FIG. 2 is a simplified view of the circuit unit of FIG. 1 installed in a housing for housing equipment. The figure (a) is a front view, and the figure (b) is a side view. FIG. 3 is a perspective view showing the circuit unit. 2 and 3 show a case where the smoothing capacitor of the circuit unit shown in FIG. 1 is composed of three capacitors.

  The power conversion device according to the first embodiment is used in, for example, an uninterruptible power supply (UPS), and is a first semiconductor switch 21 on the converter side that converts AC power into DC power. A second semiconductor switch 22 on the inverter side that converts to AC power and a smoothing capacitor 3 that attenuates both ripple currents generated in both semiconductor switches 21 and 22 are provided.

  In the first embodiment, the first connection line 91 individually connected to the first semiconductor switch 21 and the second connection line 92 individually connected to the second semiconductor switch 22 are connected to the smoothing capacitor 3. The connection lines 95 are connected in common.

  In addition, cooling fins 41 and 42 are individually provided for the semiconductor switches 21 and 22, the cooling fins 41 and 42 are arranged vertically, and the semiconductor switches 21 and 21 are arranged on the front side thereof. The smoothing capacitors 3 (31 to 33) are disposed between the two 41 and 42. The semiconductor switches 21 and 22, the cooling fins 41 and 42, and the smoothing capacitors 3 (31 to 33) are integrally attached to a frame (not shown) to constitute one circuit unit 1 as a whole.

And this circuit unit 1 is accommodated in the housing | casing 5 for apparatus accommodation. A cooling fan 6 is provided on the top of the housing 5. Further, sheet metals 71 and 72 are disposed on the back side and above the circuit unit 1 in the housing 5, and the flow of wind from the lower front surface of the housing 5 to the upper side on the back side of the housing 5 by these sheet metals 71 and 72. Guided towards.
1 to 3 show the circuit unit 1 for one phase, but in the case of AC three-phase, three circuit units 1 are connected in parallel.

  In the power converter configured as described above, the AC power supply is rectified by the switching operation of the first semiconductor switch 21 on the converter side, and the ripple current generated by the switching operation of the first semiconductor switch 21 is attenuated by the smoothing capacitor 3. Smoothed. In addition, the DC power is chopped by the second semiconductor switch 22 on the inverter side and converted into an alternating current having a constant voltage and a constant frequency, and a ripple current generated by the switching operation of the second semiconductor switch 22 is attenuated by the same smoothing capacitor 3. The

  As described above, in the power conversion device according to the first embodiment, the first and second semiconductor switches 21 and 22 and the smoothing capacitor 3 are configured as a single circuit unit 1, so The distance between the connection lines 91 to 93 of the second semiconductor switches 21 and 22 is shortened. For this reason, the high-frequency ripple current generated in each of the semiconductor switches 21 and 22 is sufficiently attenuated by the smoothing capacitor 3 commonly connected to both the semiconductor switches 21 and 22 because the inductance is small due to the short distance between the connections. . Moreover, since the first and second semiconductor switches 21 and 22 are commonly connected to the smoothing capacitor 3, the ripple current generated in each of the semiconductor switches 21 and 22 is canceled out. As a result, the ripple current associated with the switching operation of the switching elements 21 and 22 on the converter side and the inverter side can be effectively reduced by the common smoothing capacitor 3, and the number of the smoothing capacitors 3 in the entire apparatus can be reduced. It is possible to reduce the size and size of the apparatus.

  During operation of the power converter, when the cooling fan 6 is activated and wind is generated, the wind is sucked from the lower front surface of the housing 5 as shown by a broken line in FIG. The lower cooling fin 42, the smoothing capacitor 3 (31 to 33), and the upper cooling fin 41 are sequentially passed. Thereby, the temperature rise by the loss of the smoothing capacitor 3 (31-33) and the semiconductor switches 41 and 42 is suppressed. Then, the wind is guided to the upper rear side of the housing 5 by the metal plates 71 and 72 and is discharged to the outside of the housing 5 through the cooling fan 6.

Embodiment 2. FIG.
FIG. 4 shows, in a simplified manner, a state where a circuit unit is installed in a device housing case in the power conversion device according to Embodiment 2 of the present invention. FIG. 4 (a) is a front view and FIG. ) Is a side view. FIG. 5 is a perspective view showing only the circuit unit.

  In the second embodiment, the electrical connection relationship between the semiconductor switches 21 and 22 and the smoothing capacitor 3 constituting the circuit unit 1 is the same as that shown in FIG. Is different from the case of the first embodiment.

  That is, in the circuit unit 1 according to the second embodiment, the cooling fins 41 and 42 are vertically arranged, and the first and second semiconductor switches 21 and 22 are provided on the front side of the cooling fins 41 and 42, respectively. Moreover, the smoothing capacitor 3 (31-33) is arrange | positioned at the side of both the cooling fins 41 and 42. As shown in FIG. The semiconductor switches 21 and 22, the cooling fins 41 and 42, and the smoothing capacitors 3 (31 to 33) are integrally attached to a frame (not shown) to constitute one circuit unit 1 as a whole.

In this power conversion device, the wind generated by starting the cooling fan 6 is sucked from the lower front surface of the housing 5 as shown by the broken lines in FIG. The semiconductor switches 21 and 22 are cooled by passing through the fins 41 and 42. In addition, the smoothing capacitor 3 (31 to 33) is directly and efficiently cooled by the wind sucked from the lower front surface of the housing 5. That is, since the wind that has passed through the cooling fins 41 and 42 and has risen in temperature does not flow again into the smoothing capacitor 3, the temperature rise of the smoothing capacitor 3 can be suppressed and the life can be extended.
Other configurations and operational effects are the same as those of the first embodiment, and thus detailed description thereof is omitted here.

Embodiment 3 FIG.
FIG. 6 shows, in a simplified manner, a state where a circuit unit is installed in a device housing case in the power conversion device according to Embodiment 3 of the present invention. FIG. 6 (a) is a front view, FIG. ) Is a side view. FIG. 7 is a perspective view showing only the circuit unit.

  In the third embodiment, the electrical connection relationship between the semiconductor switches 21 and 22 and the smoothing capacitor 3 constituting the circuit unit 1 is the same as that shown in FIG. Is different from the first and second embodiments.

  That is, in the circuit unit 1 according to the third embodiment, the cooling fins 41 and 42 are arranged on the left and right, and the first and second semiconductor switches 21 and 22 are provided on the front side of the cooling fins 41 and 42, respectively. Further, the smoothing capacitor 3 (31 to 33) is disposed between the cooling fins 41 and 42. The semiconductor switches 21 and 22, the cooling fins 41 and 42, and the smoothing capacitors 3 (31 to 33) are integrally attached to a frame (not shown) to constitute one circuit unit 1 as a whole.

In this power conversion device, the wind generated by starting the cooling fan 6 is sucked from the lower front surface of the housing 5 as shown by the broken lines in FIG. The semiconductor switches 21 and 22 are cooled by individually passing through the fins 41 and 42. That is, since the wind that has passed through the cooling fins 41 and 42 and has risen in temperature does not flow again into the cooling fins, the semiconductor switches 21 and 22 are efficiently cooled, and the cooling effect of the semiconductor switches 21 and 22 is improved. Can extend the service life. Further, since the smoothing capacitor 3 (31 to 33) is also directly and efficiently cooled by the wind sucked from the lower front surface of the casing 5, the temperature rise of the smoothing capacitor 3 is suppressed and the life can be extended.
Other configurations and operational effects are the same as those of the first embodiment, and thus detailed description thereof is omitted here.

Embodiment 4 FIG.
FIG. 8 shows, in a simplified manner, a state where a circuit unit is installed in a device housing case in the power conversion device according to Embodiment 4 of the present invention. FIG. 8 (a) is a front view, FIG. ) Is a side view. FIG. 9 is a perspective view showing only the circuit unit.

  In the fourth embodiment, the electrical connection relationship between the semiconductor switches 21 and 22 and the smoothing capacitor 3 constituting the circuit unit 1 is the same as that shown in FIG. Is different from the case of the first to third embodiments.

  That is, in the circuit unit 1 according to the fourth embodiment, the cooling fins 41 and 42 are arranged above and below, and the semiconductor switches 21 and 22 are individually provided on the opposing surfaces of the cooling fins 41 and 42. Yes. Further, smoothing capacitors 3 (31 to 33) are arranged between the upper and lower cooling fins 41 and 42 provided with the semiconductor switches 21 and 22, respectively. The semiconductor switches 21 and 22, the cooling fins 41 and 42, and the smoothing capacitors 3 (31 to 33) are integrally attached to a frame (not shown) to constitute one circuit unit 1 as a whole.

  In the housing 5 in which the circuit unit 1 is accommodated, sheet metals 71 and 72 are provided on the back side and above the circuit unit 1, but the sheet metal 71 on the back side of the circuit unit 1 has ventilation holes. 71 a and 71 b are formed, and in accordance with this, the cooling fins 41 and 42 are also arranged so that a wind flow path is formed from the front side to the back side of the housing 5.

In this power converter, the wind generated by starting the cooling fan 6 is sucked from the lower front surface of the housing 5 as indicated by the broken line in FIG. The semiconductor switches 21 and 22 are cooled by passing from the front side toward the back side. Further, the smoothing capacitor 3 (31 to 33) is also directly and efficiently cooled by the wind sucked from the lower front surface of the housing 5. Therefore, both the semiconductor switches 21 and 22 and the smoothing capacitor 3 can improve the cooling effect and extend the lifetime.
Other configurations and operational effects are the same as those of the first embodiment, and thus detailed description thereof is omitted here.

Embodiment 5. FIG.
FIG. 10 is a circuit diagram showing a simplified connection state of the power conversion device according to Embodiment 5 of the present invention, and FIG. 11 is a simplified view showing the state where the circuit unit of FIG. 10 is installed in a housing for housing equipment. The figure (a) is a front view, and the figure (b) is a side view. FIG. 12 is a perspective view showing only the circuit unit. 11 and 12 show a case where the smoothing capacitor of the circuit unit shown in FIG. 10 is composed of six capacitors.

  The power conversion device according to the fifth embodiment includes an AC power together with a converter-side first semiconductor switch 21 that converts AC power into DC power and an inverter-side second semiconductor switch 22 that converts DC power into desired AC power. A third semiconductor switch 23 on the converter side that converts DC power into DC power, and a fourth semiconductor switch 24 on the inverter side that converts DC power into desired AC power, and further ripples generated by these on each of the semiconductor switches 21 to 24 A single smoothing capacitor 3 that attenuates the current together is provided.

  The first connection line 91 individually connected to the first semiconductor switch 21, the second connection line 92 individually connected to the second semiconductor switch 22, and the third connection line 93 connected to the third semiconductor switch 23. The fourth connection line 94 individually connected to the fourth semiconductor switch 24 is commonly connected to the connection line 95 connected to the smoothing capacitor 3.

  Further, cooling fins 41 to 44 are disposed in the casing 5 on the upper, lower, left and right sides, and the semiconductor switches 21, 22, and 23 are disposed on the opposing surfaces of the upper and lower cooling fins 41, 42, and 43, 44, respectively. , 24 are arranged individually, and the smoothing capacitor 3 is arranged between the upper and lower cooling fins 41, 42 and 43, 44. The semiconductor switches 21 to 24, the cooling fins 41 to 44, and the smoothing capacitor 3 are integrally attached to a frame (not shown) to constitute one circuit unit 1 as a whole.

  Of the metal plates 71 and 72 disposed in the housing 5 in which the circuit unit 1 is accommodated, the metal plate 71 on the back side of the circuit unit 1 is provided with vent holes 71a and 71b as in the fourth embodiment. In accordance with this, the cooling fins 41 to 44 are also arranged so that a wind flow path is formed from the front side to the back side of the housing 5.

  As described above, in the power conversion device according to the fifth embodiment, the first to fourth semiconductor switches 21 to 24 and the smoothing capacitor 3 are configured as a single circuit unit 1, so that the first to the smoothing capacitor 3 is the first. The distance between the connection lines 91 to 95 of the fourth semiconductor switches 21 to 24 is shortened. For this reason, the high-frequency ripple current generated in each of the semiconductor switches 21 to 24 can be sufficiently attenuated by the common smoothing capacitor 3 because the distance between the connections is short. In addition, since the first to fourth semiconductor switches 21 to 24 are commonly connected to the smoothing capacitor 3, the ripple current generated in each of the semiconductor switches 21 to 24 is canceled out. As a result, not only can the ripple current associated with the switching operation of the switching elements 21 to 24 on the converter side and the inverter side be effectively reduced, but the number of smoothing capacitors in the entire apparatus can be reduced, thereby reducing costs and downsizing the apparatus. It becomes possible to plan.

  In the fifth embodiment, the first and third semiconductor switches 21 and 23 are used for converters, and the second and fourth semiconductor switches 22 and 24 are used for inverters. It is also possible to use the two semiconductor switches 21 and 22 for the converter and the third and fourth semiconductor switches 23 and 24 for the inverter.

  In said Embodiment 1-5, although the case where this invention was applied to an uninterruptible power supply was demonstrated, this invention is not limited to this, After converting alternating current power into desired direct current power, The present invention can also be applied to a PWM control type power conversion device that converts a desired voltage and frequency.

It is a circuit diagram which simplifies and shows the connection state of the circuit unit of the power converter device in Embodiment 1 of this invention. The circuit unit of the power converter device of FIG. 1 is shown in a simplified manner in a device housing case, where FIG. 1 (a) is a front view and FIG. 1 (b) is a side view. It is a perspective view which shows the circuit unit in Embodiment 1 of this invention. In the power converter device which concerns on Embodiment 2 of this invention, the state which installed the circuit unit in the housing | casing for apparatus accommodation is simplified, and the figure (a) is a front view, The figure (b) is the figure. It is a side view. It is a perspective view which shows the circuit unit in Embodiment 2 of this invention. In the power converter device in Embodiment 3 of this invention, the state which installed the circuit unit in the housing | casing for apparatus accommodation is shown simplified, the figure (a) is a front view, the figure (b) is a side view. FIG. It is a perspective view which shows the circuit unit in Embodiment 3 of this invention. In the power converter device in Embodiment 4 of this invention, the state which installed the circuit unit in the housing | casing for apparatus accommodation is simplified, and the figure (a) is a front view, The figure (b) is a side view. FIG. It is a perspective view which shows the circuit unit in Embodiment 4 of this invention. It is a circuit diagram which simplifies and shows the connection state of the circuit unit of the power converter device in Embodiment 5 of this invention. 10A and 10B schematically show a state in which the circuit unit of the power conversion device of FIG. 10 is installed in a housing for device storage, in which FIG. 10A is a front view and FIG. 10B is a side view. It is a perspective view which shows the circuit unit in Embodiment 5 of this invention. It is a block diagram which shows an example of an uninterruptible power supply. It is a circuit diagram which simplifies and shows the connection state of the conventional power converter device. FIGS. 14A and 14B schematically show a state in which the circuit portion of FIG. 14 is installed in a housing for housing equipment, in which FIG. 14A is a front view and FIG. 14B is a side view. In the conventional power converter, it is a perspective view which shows the state which added the circuit unit side by side.

Explanation of symbols

1 circuit unit, 21, 23 semiconductor switch on the converter side,
22, 24 Semiconductor switch on the inverter side,
3 (31, 32, 33) smoothing capacitor, 41, 42, 43, 44 cooling fin,
5 Housing, 91, 92, 93, 94, 95 Connection line.

Claims (5)

A first semiconductor switch on the converter side that converts AC power into DC power, a second semiconductor switch on the inverter side that converts DC power into desired AC power, and a smoothing capacitor that attenuates both ripple currents generated in both semiconductor switches And a first connection line individually connected to the first semiconductor switch and a second connection line individually connected to the second semiconductor switch are common to the connection line connected to the smoothing capacitor. A power conversion device comprising a single circuit unit connected to each other. 2. The semiconductor switch according to claim 1, wherein cooling fins are individually provided in each of the semiconductor switches, the cooling fins are disposed above and below, and the smoothing capacitor is disposed on a side of the cooling fins. The power converter described. 2. The power conversion device according to claim 1, wherein each of the semiconductor switches is provided with a cooling fin individually, and the smoothing capacitor and the two cooling fins are arranged in parallel to each other. Each of the semiconductor switches is provided with a cooling fin individually, and each of the cooling fins is arranged so that an air flow path is formed from the front side to the back side of the housing for housing the equipment. The power conversion device according to claim 1. In addition to the first and second semiconductor switches, third and fourth semiconductor switches are provided, and a third connection line connected to the third semiconductor switch and a fourth connection line individually connected to the fourth semiconductor switch The power converter according to claim 1, wherein a single unit is configured by commonly connecting to a connection line connected to the smoothing capacitor.

Images