JP2018074668A - Voltage stabilizer of dc distribution system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage stabilizer of a DC distribution system capable of reducing a high frequency vibration component contained in a system voltage without increasing a size of an apparatus.SOLUTION: A voltage stabilizer 100 of a DC distribution system is interposed between a DC power supply unit 1 and a load 4 in the DC distribution system to which electric power from the DC power supply unit 1 is supplied to the load via a DC power distribution wire 2, and includes a transformer 3 having a primary winding 31 and a secondary winding 32. The primary winding 31 is connected with the DC power distribution wire 2 in series. A circuit unit 5 whose impedance viewed from the secondary winding 32 is resistive is connected with the secondary winding 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a voltage stabilization device for a DC distribution system that stabilizes a system voltage in a DC distribution system.

  In the future, it is expected that the increase in capacity and voltage of electric loads will be introduced not only in general large-scale systems but also in small-scale power systems with limited equipment installation area. This increase in the capacity of the electric load causes an increase in size of a power distribution device, particularly a transformer used for step-up / step-down and the like, resulting in an increase in device installation area.

  On the other hand, a DC power distribution method using a high-frequency transformer is attracting attention, and its application to a data center equipped with a large number of IT devices is being studied. The transformer used in the isolated DC / DC converter for step-up / step-down used in this DC power distribution system is driven at a higher frequency than the general commercial frequency, so it is smaller than the transformer used at the commercial frequency. Is possible. For this reason, the direct current distribution system has been studied.

  In a DC distribution system, a power conversion device that controls active power to a load functions as a constant power load when viewed from the DC distribution system. This constant power load has a negative resistance characteristic (current decreases as voltage rises), and disturbance is applied to the DC distribution system, which becomes a factor when the DC voltage vibrates and the system becomes unstable.

  On the other hand, the techniques described in Patent Document 1 and Patent Document 2 are conventionally known.

  In the technique described in Patent Document 1, a control amount for canceling the vibration component of the current flowing through the DC distribution line is calculated from the vibration component of the DC system voltage of the DC distribution system. Then, after adding the control amount and the preset voltage setting value for load supply to obtain the final voltage setting value, the power conversion is performed so that the load voltage becomes equal to the final voltage setting value. The device is controlled.

  In the technique described in Patent Document 2, a DC reactor main winding connected between the rectifier circuit and the smoothing capacitor, a DC reactor main winding connected via the DC reactor iron core between the rectifier circuit and the smoothing capacitor, A DC reactor device having a DC reactor auxiliary winding that is magnetically coupled is inserted. A voltage source connected to the DC reactor auxiliary winding and generating an arbitrary voltage waveform is controlled to compensate for the DC ripple.

JP 2010-183663 A JP 2002-272113 A

  In the above prior art, as the capacity of the system and the electric load is increased and the voltage is increased, a switching element having a high withstand voltage and a large capacity is required in the power converter and the voltage source. However, high-voltage and large-capacity switching elements are limited in driving at high frequencies due to thermal restrictions. For this reason, the band of the system voltage oscillation which can be reduced by control of a power converter device or a voltage source falls. In order to reduce high-frequency vibration components, there is a means for increasing the capacity of the LC filter. However, in this case, the size of the LC filter increases and the device becomes large.

  Therefore, the present invention provides a voltage stabilization device for a DC distribution system that can reduce high-frequency vibration components included in the system voltage without increasing the size of the device.

  In order to solve the above-mentioned problems, a voltage stabilizing device for a DC distribution system according to the present invention is provided between a DC power supply unit and a load in a DC distribution system in which power from a DC power supply unit is supplied to a load via a DC distribution line. Comprising a transformer comprising a primary winding and a secondary winding, the primary winding being connected in series to the DC distribution line, the secondary winding being A circuit part having a resistive impedance is connected.

  According to the present invention, when a disturbance occurs in the DC distribution system, the vibration component of the power in the DC distribution system is consumed or absorbed by the circuit unit connected to the secondary winding of the transformer. Thereby, the vibration of the voltage or the electric current which generate | occur | produces with disturbance can be suppressed, without using the power converter device and power supply device which are controlled to output the electric power which cancels the vibration component of electric power.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is a configuration diagram of a DC power distribution system including a voltage stabilization device that is Embodiment 1. FIG. It is a block diagram of the DC distribution system containing the voltage stabilization apparatus which is Example 2. FIG. The electric current of each part of the voltage stabilization apparatus in Example 2 is shown. FIG. 6 is a configuration diagram of a DC power distribution system including a voltage stabilization device that is a first modification of the second embodiment. It is a block diagram of the DC distribution system containing the voltage stabilization apparatus which is the modification 2 of Example 2. FIG. It is a block diagram of the DC distribution system containing the voltage stabilization apparatus which is the modification 3 of Example 2. FIG. It is a block diagram of the DC distribution system containing the voltage stabilization apparatus which is Example 3. FIG. It is a block diagram of the DC power distribution system containing the voltage stabilization apparatus which is Example 4. FIG. FIG. 10 is a configuration diagram of a DC power distribution system including a voltage stabilizing device that is Embodiment 5.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same reference numerals indicate the same constituent elements or constituent elements having similar functions.

  FIG. 1 is a configuration diagram of a DC power distribution system including a voltage stabilizing device that is Embodiment 1 of the present invention.

  As shown in FIG. 1, power is supplied from a DC power source 1 to a constant power load 4 via a DC distribution line 2. A voltage stabilizing device 100 is inserted between the constant power load 4 and the DC power source 1.

  The voltage stabilizing device 100 includes a transformer 3 including a primary winding 31 and a secondary winding 32 wound around an iron core. One end of the primary winding 31 is connected in series with the DC power distribution line 2, and the other end is connected to the constant power load 4. In addition, the resistor 5 is connected to the secondary winding 32 in parallel.

  The resistor 5 is a fixed resistor having a constant resistance value. The resistor 5 may be configured by connecting a plurality of resistors in series or in parallel. Although a variable resistor may be used as the resistor 5, the resistance value is held at a constant value during the operation of the voltage stabilizing device. The constant power load 4 includes, for example, a power conversion device and a load driven by direct current or alternating current.

  The voltage stabilizer 100 operates as follows. When the current and voltage of the DC distribution system vibrate due to disturbances (system faults, load fluctuations, etc.) that occur in the DC distribution system, the current and primary winding flowing through the primary winding 31 of the transformer 3 connected in series to the system The voltage generated at 31 vibrates. For this reason, since the magnetic flux in the iron core of the transformer 3 changes, a voltage is induced in the secondary winding 32. A current flows through the secondary winding 32 and the resistor 5 due to the induced voltage, and power is consumed by the resistor 5. That is, the vibration component of electric power due to the vibration component of current and voltage in the DC distribution system (primary side of the transformer 3) is transmitted to the secondary side of the transformer 3 and consumed by the resistor 5. Thereby, the vibration of the electric current and voltage in a DC distribution system is suppressed.

  As described above, according to the first embodiment, it is possible to reduce current and voltage oscillations that appear in the DC distribution system due to disturbance. Furthermore, the voltage stabilizing device can be configured with only passive components such as a transformer and a resistor. Accordingly, there is no need for a power conversion device or power supply device that is controlled to reduce current and voltage oscillations in the DC distribution system. For this reason, the restriction | limiting of the zone | band of a vibration which can be reduced is eased. In addition, an increase in device size can be suppressed.

  FIG. 2 is a configuration diagram of a DC power distribution system including a voltage stabilizing apparatus that is Embodiment 2 of the present invention.

  Hereinafter, differences from the first embodiment will be mainly described.

  In the second embodiment, the voltage stabilizing device 100 includes a three-winding transformer including a tertiary winding 33 wound around an iron core in addition to the primary winding 31 and the secondary winding 32. In the voltage stabilizing device 100, the capacitor 6 is connected in series to the primary winding 31, and the capacitor 6 is connected between the primary winding 31 and the constant power load 4. The resistor 5 is connected to the secondary winding 32 in parallel as in the first embodiment. The tertiary winding 33 is connected to the capacitor 6 in parallel. Note that the primary winding 31 and the tertiary winding 33 are wound around the iron core so that magnetic fluxes generated in the iron core of the transformer 3 cancel each other due to the currents flowing therethrough. The operation of the tertiary winding 33 will be described later.

  Also in the second embodiment, the vibration component of power due to the vibration component of the current and voltage in the DC distribution system (primary side of the transformer 3) is transmitted to the secondary side of the transformer 3 and consumed by the resistor 5. . Thereby, the vibration of the electric current and voltage in a DC distribution system is suppressed.

  Further, the operation of the second embodiment including the tertiary winding 33 will be described.

  FIG. 3 shows the current of each part (capacitor 6, primary winding 31, and tertiary winding 33) of the voltage stabilizing device 100 in the second embodiment.

  As shown in FIG. 3, of the current Idc (= DC component Idc0 + vibration component Ires0) flowing through the primary winding 31, only the vibration component Ires0 of the current Idc flows through the capacitor 6, and the current Idc of the current Idc flows through the tertiary winding 33. Only the DC component Idc0 flows. As a result, the DC component of the magnetic flux generated from the current Idc flowing through the primary winding 31 and the magnetic flux generated by the DC component Idc0 flowing through the tertiary winding 33 cancel each other. Therefore, saturation of the magnetic flux in the iron core of the transformer 3 can be prevented. As a result, the capacity and size margin required for the transformer to prevent magnetic flux saturation can be reduced, and the transformer can be miniaturized. Therefore, the voltage stabilizing device can be reduced in size.

  Next, a modification of the second embodiment will be described. In each modification, the DC power supply unit (corresponding to the DC power supply 1) is different, but the configuration of the voltage stabilizing device is the same as that of the second embodiment shown in FIG.

  FIG. 4 is a configuration diagram of a DC power distribution system including a voltage stabilizing device that is a first modification of the second embodiment.

  In the first modification, the DC power source 1 in FIG. 2 is replaced with an AC system 11 and an AC / DC converter 10. The DC power distribution system in Modification 1 is linked to the AC system 11, and the AC power of the AC system 11 is converted into DC power by the AC / DC converter 10 and supplied to the DC power distribution system.

  FIG. 5 is a configuration diagram of a DC power distribution system including a voltage stabilizing device that is a second modification of the second embodiment.

  In the second modification, the DC power source 1 in FIG. 2 is replaced with a DC system 13 and a DC / DC converter 12. The direct current distribution system in the second modification is connected to the direct current system 13 via the direct current / direct current converter 12. The DC / DC converter 12 boosts or steps down the voltage of the DC system 13 and outputs it to the DC distribution system. As described above, the DC distribution system in Modification 2 is connected to the other DC system 13, and the DC power of the DC system 13 is boosted or stepped down by the DC / DC converter 12 and supplied to the DC distribution system. The

  FIG. 6 is a configuration diagram of a DC power distribution system including a voltage stabilizing device that is a third modification of the second embodiment.

  In the third modification, the DC power source 1 in FIG. 2 is replaced with an AC system 11, an AC / DC converter 10, and a DC / DC converter 12. The DC distribution system in Modification 3 is linked to the AC system 11, AC power of the AC system 11 is converted into DC power by the AC / DC converter 10, and the output voltage of the AC / DC converter 10 is further changed to DC. The voltage is stepped up or stepped down by the DC converter 12 and supplied to the DC distribution system.

  Also in the first to third modifications, as in the second embodiment, the voltage stabilizing device 100 suppresses current and voltage oscillations in the DC distribution system. Moreover, saturation of the magnetic flux of the iron core of the transformer 3 of the voltage stabilizer 100 is prevented.

  As described above, according to the second embodiment and the first to third modifications thereof, the vibration component of the DC distribution system is suppressed and the voltage of the DC distribution system is suppressed while preventing the magnetic flux saturation of the transformer included in the voltage stabilizing device. Can be stabilized. In addition, since the DC magnetic flux in the iron core is reduced by the magnetic flux generated by flowing the DC component of the current through the tertiary winding, the tolerance required for the transformer to suppress magnetic saturation can be reduced. The transformer included in the voltage stabilizing device can be reduced in size. Thereby, a voltage stabilization apparatus can be reduced in size.

  FIG. 7 is a configuration diagram of a DC power distribution system including a voltage stabilizing apparatus that is Embodiment 3 of the present invention. Hereinafter, differences from the second embodiment will be mainly described.

  As shown in FIG. 7, unlike the second embodiment, the secondary winding 32 of the transformer 3 included in the voltage stabilizing device 100 is replaced with the resistor 5 in FIG. The AC side is connected. Further, a power storage device 8 is connected to the DC side of the AC / DC converter 7. In addition, the other structure of the voltage stabilization apparatus 100 is the same as that of Example 2 (FIG. 2).

  In the third embodiment, the vibration component of power due to the vibration component of the current and voltage in the DC distribution system (primary side of the transformer 3) passes through the primary winding 31 of the transformer 3 to the secondary side of the transformer 3. And output from the secondary winding 32. The vibration component of the power output from the secondary winding 32 is converted into DC power by the AC / DC converter 7 and stored in the power storage device 8.

  The power storage device 8 can be used as a standby power source. In addition, as the electrical storage apparatus 8, a capacitor, a storage battery, etc. are applicable, for example.

  The AC / DC converter 7 is controlled so that the impedance of the AC / DC converter 7 viewed from the secondary winding 32 has a constant resistance characteristic, that is, the power factor is 1. Almost all vibration components of the power output from the secondary winding 32 are absorbed by the power storage device 8 except for the amount consumed by the AC / DC converter 7. Thereby, the vibration of the voltage of a DC distribution system can be suppressed.

  The power consumed on the secondary side of the transformer, mainly the AC / DC converter 7, is smaller than the power consumed by the constant power load 4. For this reason, as the semiconductor switching element in the AC / DC converter 7, one having a relatively small power capacity and capable of high frequency driving can be used. For this reason, the band of the system voltage oscillation which can be reduced by the voltage stabilizing device is improved.

  As described above, according to the third embodiment, by controlling the AC / DC converter so as to have constant resistance characteristics, the vibration component of the DC distribution system can be suppressed and the voltage of the DC distribution system can be stabilized. it can. Moreover, the magnetic flux saturation of the transformer with which a voltage stabilization apparatus is provided can be suppressed similarly to Example 2. FIG. Moreover, since the vibration component of electric power is stored in the power storage device via the AC / DC converter, the efficiency of the voltage stabilizing device is improved.

  FIG. 8 is a configuration diagram of a DC power distribution system including a voltage stabilizing apparatus that is Embodiment 4 of the present invention.

  Hereinafter, differences from the second embodiment will be mainly described.

  As shown in FIG. 8, unlike the second embodiment, the secondary winding 32 of the transformer 3 provided in the voltage stabilizing device 100 is replaced with the resistor 5 in FIG. The AC side is connected. Further, a DC / DC converter 9 is connected between the DC side of the AC / DC converter 7 and the DC distribution system. The input side of the DC / DC converter 9 is connected to the DC side of the AC / DC converter 7, and the output side of the DC / DC converter 9 is connected to the constant power load 4. The other structure of the voltage stabilization apparatus 100 is the same as that of Example 2 (FIG. 2).

  As the DC / DC converter 9, for example, a step-up / step-down DC / DC converter or an insulated DC / DC converter is applied.

  In the fourth embodiment, the vibration component of electric power due to the vibration component of the current and voltage in the DC distribution system (primary side of the transformer 3) passes through the primary winding 31 of the transformer 3 to the secondary side of the transformer 3. And output from the secondary winding 32. The vibration component of the power output from the secondary winding 32 is converted into DC power by the AC / DC converter 7. This DC power is output by the DC / DC converter 9 by converting the output voltage of the AC / DC converter 7 into the voltage of the DC distribution system, and output to the DC distribution system.

  The AC / DC converter 7 is controlled so that the impedance of the AC / DC converter 7 viewed from the secondary winding 32 has a constant resistance characteristic, that is, the power factor is 1. Almost all vibration components of the power output from the secondary winding 32 are converted into DC power except for the amount consumed by the AC / DC converter 7 and the DC / DC converter. For this reason, while being able to suppress the vibration of the voltage of a DC distribution system, the efficiency of a power stabilization device improves. In addition, since the vibration component of power is returned to the DC distribution system as DC power, the power efficiency in the DC distribution system is improved.

  As described above, according to the fourth embodiment, by controlling the AC / DC converter so as to have the constant resistance characteristic, the vibration component of the DC distribution system can be suppressed and the voltage of the DC distribution system can be stabilized. it can. Moreover, the magnetic flux saturation of the transformer with which a voltage stabilization apparatus is provided can be suppressed similarly to Example 2. FIG. In addition, since the vibration component of power is returned to the DC distribution system via the AC / DC converter and the DC / DC converter, the efficiency of the voltage stabilizing device and the DC distribution system is improved.

  FIG. 9 is a configuration diagram of a DC power distribution system including a voltage stabilizing apparatus that is Embodiment 5 of the present invention.

  Hereinafter, differences from the second embodiment will be mainly described.

  As shown in FIG. 9, unlike the second embodiment, the secondary winding 32 of the transformer 3 included in the voltage stabilizing device 100 is replaced with the resistor 5 in FIG. The AC side is connected. A power storage device 8 is connected to the DC side of the AC / DC converter 7. Further, a bidirectional DC / DC converter 91 is connected between the DC side of the AC / DC converter 7 and the constant power load 4 in the DC distribution system. In addition, the other structure of the voltage stabilization apparatus 100 is the same as that of Example 2 (FIG. 2).

  In the fifth embodiment, the vibration component of power due to the vibration component of the current and voltage in the DC distribution system (primary side of the transformer 3) passes through the primary winding 31 of the transformer 3 to the secondary side of the transformer 3. And output from the secondary winding 32. The vibration component of the power output from the secondary winding 32 is converted into DC power by the AC / DC converter 7 and stored in the power storage device 8. The electric power stored in the power storage device 8 is supplied to the DC power distribution system after the output voltage of the power storage device 8 is converted into the voltage of the DC power distribution system by the bidirectional DC / DC converter 91.

  By providing the power storage device 8, the voltage stabilizing device 100 functions as a standby power source in the DC distribution system. Bidirectional DC / DC converter 91 converts the output voltage of power storage device 8 to the voltage of the DC distribution system when voltage stabilizer 100 operates as a standby power supply.

  The AC / DC converter 7 is controlled so that the impedance of the AC / DC converter 7 viewed from the secondary winding 32 has a constant resistance characteristic, that is, the power factor is 1. Almost all vibration components of the power output from the secondary winding 32 are stored in the power storage device 8 except for the amount consumed by the AC / DC converter 7 and the bidirectional DC / DC converter 91. For this reason, while being able to suppress the vibration of the voltage of a DC distribution system, the efficiency of a power stabilization device improves. Further, since the stored electric power can be supplied to the DC distribution system via the bidirectional DC / DC converter 91, a reserve power supply for the DC distribution system can be secured without providing a special power supply device. And since the vibration component of electric power is supplied to a DC distribution system as backup DC power in this way, the power efficiency in the DC distribution system is improved.

  In the fifth embodiment, the DC power stabilized by the voltage stabilizing device 100 is converted into the charging voltage of the power storage device 8 by the bidirectional DC / DC conversion device 91 in the DC distribution system, and the power storage device 8 Can be charged. For this reason, the amount of power storage as a standby power supply can be reliably ensured.

  As described above, according to the fifth embodiment, by controlling the AC / DC converter so as to have a constant resistance characteristic, the vibration component of the DC distribution system can be suppressed and the voltage of the DC distribution system can be stabilized. it can. Moreover, the magnetic flux saturation of the transformer with which a voltage stabilization apparatus is provided can be suppressed similarly to Example 2. FIG. In addition, the vibration component of the electric power is stored in the power storage device via the AC / DC converter, and is supplied to the DC distribution system via the power storage device and the bidirectional DC / DC converter, so that the voltage stabilizing device and The efficiency of the DC distribution system is improved. In addition, since the DC power stabilized by the voltage stabilization device is stored in the power storage device via the bidirectional DC / DC converter, the reliability of the voltage stabilization device as a standby power source for the DC distribution system is improved. To do.

  In addition, this invention is not limited to the Example mentioned above, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  For example, in Examples 3 to 5, depending on the magnitude of the vibration component of the power, the power or the amount of power that can be handled by the AC / DC converter or the power storage device, the AC / DC converter has a resistance on the AC side or the DC side. The devices may be connected in parallel so that part of the power is consumed by the resistors. Moreover, you may apply the structure (Modifications 1-3 of Example 2) shown to FIGS. 4-6 to Example 1, 3-5. Further, instead of the constant power load, a general DC / AC converter or a DC / DC converter and a load driven thereby may be applied.

1: DC power supply, 2: DC distribution line, 3: transformer, 4: constant power load, 5: resistor,
6: capacitor, 7: AC / DC converter, 8: power storage device, 9: DC / DC converter,
10: AC / DC converter, 11: AC system, 12: DC / DC converter,
13: DC system, 31: primary winding, 32: secondary winding, 33: tertiary winding,
91: Bidirectional DC / DC converter, 100: Voltage stabilizer

Claims (14)

In a voltage stabilizing device for a DC distribution system inserted between the DC power supply unit and the load in a DC distribution system in which power from a DC power supply unit is supplied to a load via a DC distribution line,
Comprising a transformer with a primary winding and a secondary winding;
The primary winding is connected in series to the DC distribution line,
A voltage stabilizing device for a DC power distribution system, wherein the secondary winding is connected to a circuit unit having an impedance as viewed from the secondary winding. In the voltage stabilizing device of the DC distribution system according to claim 1,
The voltage stabilizing device for a DC power distribution system, wherein the circuit unit includes a resistor connected in parallel to the secondary winding. In the voltage stabilizing device of the DC distribution system according to claim 1,
The transformer comprises a tertiary winding;
A capacitor is connected in series to the primary winding,
The tertiary winding is connected in parallel to the capacitor;
Voltage stabilization of a DC distribution system, wherein the primary winding and the tertiary winding are wound around the iron core so that magnetic fluxes generated in the iron core of the transformer cancel each other due to currents flowing through the primary winding and the tertiary winding, respectively. apparatus. In the voltage stabilization apparatus of the DC distribution system according to claim 3,
In the capacitor, a vibration component of the current flowing in the primary winding flows,
A voltage stabilizing device for a DC power distribution system, wherein a DC component of a current flowing through the primary winding flows through the tertiary winding. In the voltage stabilizing device of the DC distribution system according to claim 1,
The DC power supply unit is
AC system,
An AC / DC converter that converts AC power of the AC system into DC power and supplies the DC power to the DC power distribution system;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilizing device of the DC distribution system according to claim 1,
The DC power supply unit is
DC system,
A DC / DC converter for supplying DC power of the DC system to the DC distribution system by stepping up or down the voltage of the DC system;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilizing device of the DC distribution system according to claim 1,
The DC power supply unit is
AC system,
An AC / DC converter for converting AC power of the AC system into DC power;
A DC / DC converter that supplies the DC power output from the AC / DC converter to the DC distribution system by stepping up or down the output voltage of the AC / DC converter;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilizing device of the DC distribution system according to claim 1,
The circuit section is
An AC / DC converter whose AC side is connected to the secondary winding;
A power storage device connected to the DC side of the AC / DC converter;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilization apparatus of the DC distribution system according to claim 8,
The AC / DC converter is controlled so that the impedance viewed from the secondary winding has a constant resistance characteristic. In the voltage stabilizing device of the DC distribution system according to claim 1,
The circuit section is
An AC / DC converter whose AC side is connected to the secondary winding;
A DC / DC converter connected between a DC side of the AC / DC converter and the load;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilization apparatus of the DC distribution system according to claim 10,
The AC / DC converter is controlled so that the impedance viewed from the secondary winding has a constant resistance characteristic. In the voltage stabilizing device of the DC distribution system according to claim 1,
The circuit section is
An AC / DC converter whose AC side is connected to the secondary winding;
A power storage device connected to the DC side of the AC / DC converter;
A bidirectional DC / DC converter connected between the power storage device and the load;
A voltage stabilizing device for a DC power distribution system comprising: In the voltage stabilization apparatus of the DC distribution system according to claim 12,
The AC / DC converter is controlled so that the impedance viewed from the secondary winding has a constant resistance characteristic. In the voltage stabilization apparatus of the DC distribution system according to claim 12,
A voltage stabilization device for a DC distribution system, wherein DC power of the DC distribution system is stored in the power storage device via the bidirectional DC / DC converter.

Images