JP2005065400A - Power storage system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power storage system which can effectively prevent a temperature rise of a lead terminal. <P>SOLUTION: The power from a three-phase power source 6 is stored in a superconductive coil 1 via an AC/DC converter 8. When an instantaneous drop detector 7 detects the instantaneous drop of three-phase power 6, an AC/DC converter 8 takes out specified power from the energy stored in a superconductive coil 1, and outputs it to load 10 via a changeover switch 9. Together with it, a compressor controller 16 maximizes the frequency of the power to be supplied to a compressor 15, whereby the number of revolutions of the compressor 15 becomes maximum, and the freezing capacity of a pulse tube freezer 2 becomes maximum. Since a lead terminal 11 coupled with the cooling head 21 of the pulse tube freezer is cooled with its maximum capacity, the temperature rise due to the heating of the lead terminal 1 is prevented effectively even if the current increases sharply when the power is taken out of the superconductive coil 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power storage device using superconductivity.

  Conventionally, as this type of power storage device, so-called SMES (superconducting power storage device) is known which stores power energy as magnetic energy in a superconducting coil. When the power storage device is installed in a semiconductor manufacturing factory, for example, and an instantaneous drop (hereinafter referred to as an instantaneous drop) occurs in the power line of the semiconductor manufacturing factory, the voltage drops for about 0.1 seconds. It is used as a voltage sag compensator that restores a load-side power line to a predetermined voltage.

  The power storage device constantly monitors the voltage value of the power line. When the voltage value is normal, the power storage device receives power from the power line and stores the energy of the power in the superconducting coil. And when the fall of the voltage value of the said electric power line is detected and the start of an instantaneous drop is detected, electric power is taken out from the energy stored in the said superconducting coil, and the electric power line (henceforth an electric power load line is called hereafter) The voltage value of this power load line is recovered quickly.

  The power storage device cools the superconducting coil made of a superconductor to a cryogenic temperature, and a lead terminal for inputting / outputting power to / from the superconducting coil is also made of a superconductor and cooled to a cryogenic temperature. doing.

  As a refrigerator for cooling the superconducting coil and the lead terminal, a pulse tube refrigerator using helium gas as a working fluid is used. This pulse tube refrigerator is connected to a compressor that discharges high-pressure helium gas, and adjusts the refrigerating capacity by controlling the rotational speed of the compressor (see, for example, JP-A-2002-106991: Patent Document 1). ).

  In the power storage device, a cooling head of the pulse tube refrigerator is disposed in a heat shield that accommodates the superconducting coil and the lead terminal, and the lead terminal is connected to the cooling head. A temperature sensor is provided in the heat shield, and the amount of cold generated by the cooling head is adjusted by controlling the number of revolutions of the compressor based on the detected value of the temperature sensor, so that the superconducting coil and the lead are adjusted. The terminal temperature is kept at a very low temperature.

However, when the conventional power storage device detects an instantaneous drop in the power line and takes out power from the superconducting coil, a relatively large amount of heat is generated in the lead terminal due to a sudden increase in current flowing through the lead terminal. Happens. In the superconducting coil as well, a relatively large amount of heat is generated due to a sudden change in electric field due to a rapid discharge and subsequent power reception. The temperature increase in the heat shield due to the heat generation of the lead terminal and the superconducting coil is detected by the temperature sensor, and the rotational speed of the compressor is increased according to the detection value of the temperature sensor. There is a time difference between the start of the rise and the increase of the refrigeration capacity of the pulse tube refrigerator. Therefore, depending on the amount of heat generated, there is a problem that the temperature of the superconducting coil and the lead terminal may rise to a temperature causing superconducting breakdown.
JP 2002-106991 A (FIG. 1)

  Therefore, an object of the present invention is to provide a power storage device that can effectively prevent temperature rise of lead terminals and superconducting coils.

In order to achieve the above object, a power storage device of the present invention includes a power storage unit that stores energy of power,
A voltage sag detecting means for detecting an instantaneous drop in the voltage of the power line;
When the instantaneous voltage drop detecting means detects an instantaneous drop in the voltage of the power line, an output means for taking out the power from the energy stored in the power storage unit and outputting it to the power load line;
A refrigerator mounted on the power storage unit;
A compressor for compressing a refrigerant to be supplied to the refrigerator;
First frequency changing means for changing the frequency of power supplied to the compressor;
Second frequency changing means for changing the frequency of power supplied to the drive unit of the refrigerator,
When the instantaneous voltage drop detecting means detects an instantaneous drop in the voltage of the power line, at least one of the first frequency changing means or the second frequency changing means is commanded, and at least one of the drive units of the compressor or the refrigerator Frequency maximizing means for maximizing the frequency of the power supplied to one side is provided.

  According to the power storage device having the above configuration, when the instantaneous voltage drop of the power line is detected by the voltage sag detecting unit, that is, when a voltage sag is detected, the output unit generates power from the energy stored in the power storage unit. Is taken out and this power is output to the power load line (load-side power line). At the same time, the frequency of the electric power supplied to the compressor is maximized by the first frequency changing means that has received a command from the frequency maximizing means. Moreover, the frequency of the electric power supplied to the drive unit of the refrigerator is maximized by the second frequency changing unit that has received the instruction from the frequency maximizing unit. This maximizes the refrigeration capacity of the refrigerator. Therefore, the power storage unit on which the refrigerator is mounted is cooled with the maximum cooling capacity with almost no time difference from when the energy is extracted. As a result, the power storage unit is effectively prevented from rising in temperature due to power extraction. Therefore, for example, superconducting breakdown of the power storage unit is effectively prevented.

  The frequency maximizing means instructs one or both of the first frequency changing means and the second frequency changing means to supply the frequency of electric power to be supplied to the compressor, and the refrigerator. One or both of the frequencies of the power supplied to the drive unit may be maximized. In any case, it is sufficient that the refrigeration capacity of the refrigerator can be maximized quickly.

In one embodiment, the power storage unit includes a superconducting coil.
The refrigerator is a refrigerator that cools the superconducting coil.

  According to the power storage device of one embodiment, the power storage unit includes a superconducting coil, and the energy of the power is stored in the superconducting coil. This superconducting coil is cooled by the refrigerator. When the voltage sag is detected by the voltage sag detecting means and the power is extracted from the energy stored in the superconducting coil by the output means, the first frequency changing means and the second frequency changing by the frequency maximizing means. The refrigeration capacity of the refrigerator is maximized by a command to the means. Therefore, the superconducting coil cooled by the refrigerator is cooled with the maximum cooling capacity with almost no time difference from when electric power is extracted. As a result, in the superconducting coil, even if there is a significant change in the magnetic field due to a rapid discharge and subsequent power reception, no heat is generated, and therefore a temperature rise due to heat generation is effectively prevented. Therefore, the superconducting breakdown of the superconducting coil is effectively prevented.

In one embodiment, the power storage unit includes a superconducting coil.
The refrigerator is a refrigerator that cools the lead terminal of the superconducting coil.

  According to the power storage device of one embodiment, the power storage unit includes a superconducting coil, and the energy of the power is stored in the superconducting coil. The lead terminal for inputting / outputting electric power to / from the superconducting coil is cooled by the refrigerator. When the voltage sag is detected by the voltage sag detecting means and the power is extracted from the energy stored in the superconducting coil by the output means, the first frequency changing means and the second frequency changing by the frequency maximizing means. The refrigeration capacity of the refrigerator is maximized by a command to the means. Therefore, the lead terminal cooled by the refrigerator is cooled with the maximum cooling capacity with almost no time difference from when the electric power is taken out from the superconducting coil. As a result, the lead terminal hardly generates heat even when the current increases suddenly by taking out the electric power, so that temperature rise due to heat generation is effectively prevented. Therefore, the superconducting breakdown of the lead terminal is effectively prevented.

  As is clear from the above, according to the power storage device of the present invention, the power storage unit that stores the energy of the power, the instantaneous voltage drop detecting unit that detects the instantaneous decrease in the voltage of the power line, and the instantaneous voltage drop detecting unit include When an instantaneous drop in the voltage of the power line is detected, output means for extracting power from the energy stored in the power storage unit and outputting it to the power load line, a refrigerator mounted on the power storage unit, and A compressor for compressing refrigerant supplied to the refrigerator; first frequency changing means for changing a frequency of electric power supplied to the compressor; and a second frequency for changing the frequency of electric power supplied to the drive unit of the refrigerator. When the change means and the instantaneous drop detection means detect an instantaneous drop in the voltage of the power line, the compressor is instructed to at least one of the first frequency change means or the second frequency change means, and the compressor Or a frequency maximizing means for maximizing the frequency of power supplied to at least one of the drive units of the refrigerator, so that when the sag detecting means detects a power line sag, the output means Predetermined power is output from the conduction coil to the power load line, and the frequency of the power supplied to the compressor is maximized by the first frequency changing means that has received a command from the frequency maximizing means. The frequency of the electric power supplied to the drive unit of the refrigerator is maximized by the second frequency changing unit that receives the instruction of the frequency maximizing unit, and the refrigerating capacity of the refrigerator is maximized. Accordingly, since the power storage unit can be cooled with the maximum capacity without causing a time difference from taking out the energy from the superconducting coil, the power storage unit can effectively prevent the temperature rise associated with the extraction of the power. . As a result, for example, superconducting breakdown of the power storage unit can be effectively prevented.

  Further, according to the power storage device of one embodiment, the power storage unit has a superconducting coil, and the refrigerator is a refrigerator that cools the superconducting coil, and thus is cooled by the refrigerator. Superconducting coils can be cooled with maximum cooling capacity with little time difference from when energy is extracted. As a result, in the superconducting coil, even if there is a significant change in the magnetic field due to sudden discharge and subsequent power reception, the temperature rise due to heat generation can be effectively prevented, and superconducting breakdown of this superconducting coil can be effectively prevented. Can be prevented.

  Also, according to the power storage device of one embodiment, the power storage unit has a superconducting coil, and the refrigerator is a refrigerator that cools the lead terminal of the superconducting coil. The lead terminal to be cooled can be cooled with the maximum cooling capacity with almost no time difference from when energy is extracted from the superconducting coil. As a result, even if the current suddenly increases due to the extraction of the electric power for the lead terminal, the temperature rise due to heat generation can be effectively prevented, and the superconducting breakdown of the lead terminal can be effectively prevented.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a schematic diagram illustrating a power storage device according to a first embodiment of the present invention. This power storage device is a so-called SMES that stores power energy as magnetic energy in a superconducting coil. This power storage device is formed as a voltage sag compensator that recovers the power load line to a predetermined voltage when a sag occurs in the power line for about 0.1 seconds due to lightning or the like. .

  The power storage device includes a superconducting coil 1 formed of a superconductor and a pulse tube refrigerator 2 as a refrigerator, and the superconducting coil 1 and the cooling head 21 of the pulse tube refrigerator 2 are It is housed in the heat shield 4. The superconducting coil 1 is provided with lead terminals 11 for inputting / outputting electric power to / from the superconducting coil 1. The lead terminal 11 is made of a superconductor. The superconducting coil 1, the lead terminal 11, and the heat shield 4 form the power storage unit 100 of the present invention.

  This power storage device is connected to a three-phase power supply 6 as a power line, and constantly monitors the voltage value of the three-phase power supply 6 and detects an instantaneous drop of the voltage value, that is, a momentary drop. A voltage sag detector 7 is provided as a voltage sag detector. The three-phase power source 6 is connected to the AC / DC converter 8 via the voltage sag detector 7 and the changeover switch 9. The AC / DC converter 8 converts the AC power of the three-phase power source 6 into DC power and inputs the DC power to the superconducting coil 1 via the lead terminal 11. The AC / DC converter 8 and the changeover switch 9 function as output means based on a signal received from the voltage sag detector 7 when the voltage sag detector 7 detects a voltage sag. That is, upon receiving a signal indicating occurrence of a voltage sag from the voltage sag detector 7, the AC / DC converter 8 converts a predetermined amount of DC power extracted from the energy stored in the superconducting coil 1 to AC power. The changeover switch 9 is configured to output the converted AC power to the load 10 side. The load 10 is a power load line to which a device or the like that should avoid a sag is connected.

  A lead terminal 11 provided on the superconducting coil 1 is connected to a cooling head 21 of the pulse tube refrigerator. The cooling head 21 of the pulse tube refrigerator is connected to the tip of a pulse tube (not shown), and the other end of the pulse tube is fixed to the refrigerator main body 22 located outside the heat shield 4. Although not shown, the refrigerator main body 22 includes a rotary valve formed to be able to communicate with the other end of the pulse tube, a motor that drives the rotary valve, and a buffer tank that communicates with the tip of the pulse tube. Is provided. The refrigerator main body 22 is connected to a discharge side and a suction side of a compressor 15 that compresses helium gas as a refrigerant via a high-pressure pipe and a low-pressure pipe, respectively.

  As the rotary valve in the refrigerator main body 22 is rotationally driven by a motor, the high-pressure pipe and the low-pressure pipe are sequentially communicated with the other end of the pulse pipe through the rotary valve. As a result, a pressure fluctuation of the pulsed helium gas is given to the other end of the pulse tube, cold is generated at the tip of the pulse tube, and a cryogenic temperature is generated in the cooling head.

  The compressor 15 has a built-in motor that drives a compression unit that performs a compression operation of helium gas, and is connected to a compressor control device 16 that controls electric power supplied to the motor. The compressor control device 16 changes the frequency of the electric power supplied from the power supply 17 and outputs it to the compressor 15 as an inverter unit, and a control unit for controlling the operation of the inverter unit. Have The control unit is configured to supply electric power of a predetermined frequency to the compressor 15 according to the temperature in the heat shield 4, and that the instantaneous drop has occurred from the instantaneous drop detector 7. When a signal is received, it has a function of increasing the frequency of the power supplied to the compressor 15 to the maximum value. That is, it has a function as frequency maximizing means.

  The refrigerator main body 22 is connected to a valve control device 19 that controls power supplied to a motor as a drive unit that drives a rotary valve (not shown). The valve control device 19 includes an inverter unit as a second frequency changing unit that changes the frequency of the power supplied from the power supply 20 and a control unit that controls the operation of the inverter unit. The control unit supplies electric power having a predetermined frequency corresponding to the temperature in the heat shield 4 to a motor that drives the rotary valve, and outputs a signal indicating that a voltage sag has occurred from the voltage sag detector 7. When received, it has a function of increasing the frequency of the power supplied to the motor of the refrigerator main body 22 to the maximum value. That is, it has a function as frequency maximizing means.

  When the voltage of the three-phase power source 8 detected by the voltage sag detector 7 is a predetermined rated voltage, the power storage device having the above-described configuration uses the AC / DC converter 8 to convert the power from the three-phase power source into direct current. The electric power is converted into electric power and input to the superconducting coil 1 through the lead terminal 11, and electric power is stored in the superconducting coil 1 as electromagnetic energy. Further, the compressor control device 16 supplies power of a predetermined frequency to the compressor 15 according to the temperature in the heat shield 4, and the valve control device 19 drives the rotary valve of the refrigerator main body. Power of a predetermined frequency is supplied to the motor. As a result, the superconducting coil 1 and the lead terminal 11 are maintained at an extremely low temperature and superconductivity is maintained.

  On the other hand, when a sag occurs in the three-phase power source 6, the sag detector 7 detects the occurrence of the sag and receives the signal indicating the occurrence of sag from the sag detector 7. The / DC converter 8 takes a predetermined amount of DC power from the energy stored in the superconducting coil 1 and converts it into AC power. The changeover switch 9 outputs this AC power to the load 10 side. As a result, the voltage value on the load 10 side is restored to a predetermined value with almost no drop.

  When the voltage sag detector 7 detects the occurrence of the voltage sag, the control unit of the compressor control device 16 that has received a signal indicating the voltage sag from the voltage sag detector 7 By controlling, the frequency of the power supplied to the compressor 15 is maximized. As a result, in the compressor 15, the rotation speed of the motor and the compression unit becomes the maximum value, and the pressure of the discharged helium gas from the compressor 15 becomes the maximum value. In addition, the control unit of the valve control device 19 that has received a signal indicating the occurrence of a voltage sag from the voltage sag detector 7 controls the inverter unit, and the frequency of the power supplied to the motor of the refrigerator main body 22. To the maximum value. Thereby, the rotational speed of the motor in the refrigerator main body 22 becomes the maximum value, and the rotational speed of the rotary valve driven by this motor becomes the maximum value. As a result, the cooling capacity of the pulse tube refrigerator 2 is maximized, and the cooling capacity of the cooling head 21 is maximized. Therefore, the lead terminal 11 connected to the superconducting coil 1 is cooled with the maximum capacity without causing a time difference from that when a predetermined amount of DC power is extracted from the energy stored in the superconducting coil 1. . As a result, even if a relatively large value of current flows through the lead terminal 11 in accordance with the extraction of electric power from the superconducting coil 1, the temperature rise due to heat generation hardly occurs. Therefore, occurrence of superconducting breakdown of the lead terminal 11 and the superconducting coil can be effectively prevented.

  FIG. 2 is a schematic diagram illustrating a power storage device according to the second embodiment. The power storage device of the second embodiment controls the frequency of power supplied to the compressor and the refrigerator main body for the refrigerator that cools the superconducting coil 1 together with the refrigerator 2 that cools the lead terminals 11. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the power storage device of the present embodiment, the superconducting coil 1 is immersed in the liquid helium 51 filled in the container 5, and the superconducting coil 1 is cooled via the liquid helium. The superconducting coil 1, the lead terminal 11, the container 5 and the liquid helium 51, and the heat shield 4 form the power storage unit 200 of the present invention. The cooling head 31 of the two-stage pulse tube refrigerator 3 is connected to the container 5 filled with liquid helium. The cooling head 31 is provided at the tip of a two-stage regenerator that is sequentially connected, and the two-stage regenerator is connected to two pulse tubes, respectively. The two pulse tubes are connected to a refrigerator main body 32 fixed to the outside of the heat shield 4, and helium gas whose pressure varies in a pulse shape is supplied from the refrigerator main body 32. Due to the pulsed pressure variation of the helium gas, cold is generated at the tip of each pulse tube, the two-stage regenerators are sequentially cooled, and a cryogenic temperature is generated at the tip of the second-stage regenerator. It has become.

  The refrigerator main body 32 is connected to the discharge side and the suction side of the helium gas compressor 35 in the same manner as the refrigerator main body 22 of the pulse tube refrigerator that cools the lead terminals. The helium gas compressor 35 includes a compression unit that performs a compression operation of helium gas and a motor that drives the compression unit, and the frequency of electric power supplied to the motor is a compressor control device (not shown). It is controlled by. As in the pulse tube refrigerator 2 having a lead terminal, the compressor control device includes an inverter unit serving as a first frequency changing unit that changes and outputs the frequency of the power supplied from the power source, And a control unit for controlling the operation. The control unit is configured to supply power of a predetermined frequency to the compressor 35 according to the temperature of the liquid helium 51 in the container 5. In addition, when a signal indicating that a voltage sag has occurred is received from the voltage sag detector 7, it has a function of increasing the frequency of the power supplied to the compressor 35 to the maximum value, and serves as a frequency maximizing means. It has a function.

  The refrigerator main body 32 includes a rotary valve (not shown) and a motor that drives the rotary valve, and is connected to a valve control device (not shown) that controls power supplied to the motor. This valve control device controls the operation of the inverter unit as second frequency changing means for changing the frequency of the electric power supplied from the power source, and the operation of this inverter unit, as in the pulse tube refrigerator 2 of the lead terminal. And a control unit. This control unit supplies power of a predetermined frequency to the motor according to the temperature of the liquid helium 51 in the container 5. Further, when a signal indicating that a voltage sag has occurred is received from the voltage sag detector 7, the frequency of the power supplied to the motor of the refrigerator main body 32 is increased to the maximum value, thereby functioning as a frequency maximizing means. Have

  In the power storage device of the second embodiment, when a voltage sag occurs in the three-phase power supply 6, the voltage sag detector 7 detects the voltage sag, and based on the signal from the voltage sag detector 7, the above The AC / DC converter 8 takes out a predetermined amount of DC power from the energy stored in the superconducting coil 1 and converts it into AC power, and the changeover switch 9 outputs the AC power to the load 10 side. As a result, the voltage value on the load 10 side is restored to a predetermined value with almost no drop.

  Further, when the voltage sag detector 7 detects the occurrence of the voltage sag, the control unit of the compressor control device that has received a signal from the voltage sag detector 7 controls the inverter unit to control the compressor. The frequency of the power supplied to 35 is maximized. Moreover, the control part of the said valve control apparatus receives the signal from the said voltage drop detector 7, controls the said inverter part, and makes the frequency of the electric power supplied to the motor of the said refrigerator main body 32 the maximum value. . As a result, the pressure of the helium gas supplied to the refrigerator main body 32 becomes the maximum value, and the rotation speed of the rotary valve driven by the motor in the refrigerator main body 22 becomes the maximum value. As a result, the refrigerating capacity of the two-stage pulse tube refrigerator 3 is maximized, and the cooling capacity of the cooling head 31 is maximized. Therefore, the liquid helium 51 in which the superconducting coil 1 is immersed is cooled with the maximum capacity with almost no time difference from when a predetermined amount of DC power is extracted from the energy stored in the superconducting coil 1. . As a result, the superconducting coil 1 hardly generates a temperature rise due to heat generation even when a rapid magnetic field change due to the rapid discharge and the subsequent power reception occurs as the electric power is taken out. Therefore, the superconducting breakdown of the superconducting coil 1 can be effectively prevented.

  In addition, the refrigeration capacity of the pulse tube refrigerator 2 that cools the lead terminal 11 by the compressor control device 16 and the valve control device 19 that have received a signal from the voltage sag detector 7 as in the first embodiment. Is maximized, and the lead terminal 11 is cooled with the maximum capacity to prevent superconducting breakdown.

  As described above, when the voltage sag detector 7 detects a voltage sag of the three-phase power source 6, the pulse tube refrigerator 2 that cools the lead terminal 11 and the two-stage pulse tube that cools the superconducting coil 1. Since the refrigerating capacity with the refrigerator 3 is set to the maximum capacity, an increase in the temperature of the power storage unit due to the sag compensation operation is effectively prevented. As a result, the superconducting breakdown of the lead terminal 11 and the superconducting coil 1 can be effectively prevented, so that the power storage device can stably perform the sag compensation operation.

  In the above embodiment, both the pulse tube refrigerator 2 that cools the lead terminal 11 and the two-stage pulse tube refrigerator 3 that cools the superconducting coil 1 are used as signals from the voltage drop detector 7. Although the control for maximizing the refrigerating capacity is performed based on this, the control for maximizing the refrigerating capacity may be performed only for the two-stage pulse tube refrigerator 3 that cools the superconducting coil 1.

  In the above-described embodiment, the pulse tube refrigerator 2 and the two-stage pulse tube refrigerator 3 are used as the refrigerator, but other refrigerators such as a Gifford-McMahon refrigerator and a Stirling refrigerator may be used. The two-stage pulse tube refrigerator 3 may be a single-stage type or may have two or more cooling stages. The refrigerant used in the refrigerator is not limited to helium gas, and other refrigerants may be used.

It is the schematic which shows the electric power storage apparatus of 1st Embodiment of this invention. It is the schematic which shows the electric power storage apparatus of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superconducting coil 2 Pulse tube refrigerator 4 Heat shield 6 Three-phase power supply 7 Voltage drop detector 8 AC / DC converter 9 Changeover switch 10 Load 11 Lead terminal 15 Compressor 16 Compressor control device 17 Power supply 19 Valve control device 20 Power source 21 Cooling head 22 Refrigeration unit body 100 Power storage unit

Claims (3)

An electric power storage unit (100, 200) for storing electric energy;
A voltage sag detecting means (7) for detecting an instantaneous drop in the voltage of the power line;
When the instantaneous drop detecting means (7) detects an instantaneous drop in the voltage of the power line (6), power is extracted from the energy stored in the power storage unit (100, 200) and the power load line (10). Output means (8, 9) for outputting to
A refrigerator (2, 3) mounted on the power storage unit (100, 200);
A compressor (15, 35) for compressing refrigerant supplied to the refrigerator (2, 3);
First frequency changing means for changing the frequency of power supplied to the compressor (15, 35);
Second frequency changing means for changing the frequency of power supplied to the drive unit of the refrigerator (2, 3);
When the instantaneous voltage drop detecting means (7) detects an instantaneous drop in the voltage of the power line (6), the compressor (15) is instructed to at least one of the first frequency changing means or the second frequency changing means. , 35) or a frequency maximizing means for maximizing the frequency of power supplied to at least one of the drive units of the refrigerator (2, 3). The power storage device according to claim 1,
The power storage unit (100, 200) has a superconducting coil (1),
The power storage device according to claim 1, wherein the refrigerator is a refrigerator (3) for cooling the superconducting coil (1). The power storage device according to claim 1,
The power storage unit (100, 200) has a superconducting coil (1),
The power storage device according to claim 1, wherein the refrigerator is a refrigerator (2) that cools the lead terminal (11) of the superconducting coil.

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