Patent Application
20250146146
Embodiments described herein relate generally to an electrolytic cell power supply device.
There is an electrolytic cell power supply device that causes an electrolytic cell to perform electrolysis by supplying DC power between an anode and a cathode of the electrolytic cell. The electrolytic cell power supply device is connected to an alternating current power system, converts the AC power supplied from the power system into DC power corresponding to the electrolytic cell, and supplies the DC power after the conversion between the anode and the cathode of the electrolytic cell. For example, the electrolytic cell produces a product such as hydrogen or the like by performing electrolysis according to the supply of the DC power from the electrolytic cell power supply device.
When a power interruption of the power system occurs and the supply of the DC power to the electrolytic cell is undesirably stopped, a reverse current, which is a current in the opposite direction of normal electrolysis inside the electrolytic cell (a current in the opposite direction when viewed from the electrodes inside the electrolytic cell), may undesirably flow in such an electrolytic cell power supply device. The generation of such a reverse current undesirably causes degradation of the electrolytic cell. For example, the cathode of the electrolytic cell may be undesirably oxidized.
Therefore, a corrosion prevention power supply that includes a battery or the like is prepared separately from the electrolytic cell power supply device; and the generation of the reverse current and the degradation of the electrolytic cell due to the generation of the reverse current are suppressed by supplying power from the corrosion prevention power supply to the electrolytic cell when a power interruption occurs.
However, in a configuration in which a separate corrosion prevention power supply is prepared, the number of components is increased, and the equipment configuration is undesirably complex. For example, there is a risk that this may undesirably result in larger equipment, increased costs, etc. It is therefore desirable for the electrolytic cell power supply device to be able to suppress the generation of the reverse current with a simpler configuration.
Japanese Patent No. 5797621
An embodiment of the invention provides an electrolytic cell power supply device that can suppress the generation of a reverse current with a simpler configuration.
According to an embodiment of the invention, an electrolytic cell power supply device is provided, the electrolytic cell power supply device causes an electrolytic cell to perform electrolysis by supplying direct current power between an anode and a cathode of the electrolytic cell, the electrolytic cell power supply device includes: a first converter configured to convert alternating current power supplied from a power system into direct current power; a storage element configured to store direct current power output from the first converter; a second converter configured to convert the direct current power stored in the storage element into other direct current power corresponding to the electrolytic cell, and supply the direct current power after the conversion between the anode and the cathode of the electrolytic cell; and a control device configured to control operations of the first and second converters, the control device includes a normal operation mode when the power system is normal, the normal operation mode controlling the operations of the first and second converters to supply, to the electrolytic cell, direct current power for performing electrolysis based on the alternating current power supplied from the power system, and a corrosion prevention operation mode in a power interruption of the power system, the corrosion prevention operation mode controlling the operation of the second converter to suppress a generation of a reverse current by supplying, to the electrolytic cell, a direct current power that is based on the direct current power stored in the storage element and is smaller than the direct current power supplied to the electrolytic cell in the normal operation mode, the reverse current being a current component flowing in an opposite direction of normal electrolysis inside the electrolytic cell.
According to embodiments of the invention, an electrolytic cell power supply device that can suppress the generation of a reverse current with a simpler configuration is provided.
Embodiments will now be described with reference to the drawings.
The drawings are schematic and conceptual; and the relationships between the thicknesses and widths of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. Also, the dimensions and proportions may be illustrated differently among drawings, even for identical portions.
In the specification and drawings, components similar to those described previously or illustrated in an antecedent drawing are marked with the same reference numerals; and a detailed description is omitted as appropriate.
As illustrated in
For example, the electrolytic cell 2 produces a product such as hydrogen or the like by performing electrolysis according to the supply of the DC power from the electrolytic cell power supply device 10. The electrolytic cell 2 may further include, for example, an ion exchange membrane (a diaphragm) located between the anode and the cathode, etc. The configuration of the electrolytic cell 2 includes at least the anode 2a and the cathode 2b, and may be any configuration that can perform electrolysis of an electrolytic solution or the like by supplying the DC power between the anode 2a and the cathode 2b.
The electrolytic cell power supply device 10 is connected to the electrolytic cell 2 and connected to a power system 4. The power system 4 is an alternating current power system. For example, the electrolytic cell power supply device 10 is connected to the power system 4 via a transformer 6, etc. The power of the power system 4 is, for example, three-phase AC power. However, the power of the power system 4 is not limited to three-phase AC power and may be single-phase AC power, etc.
The first converter 11 is connected with the power system 4. For example, the first converter 11 is connected with the power system 4 via the transformer 6, etc. The first converter 11 converts the AC power supplied from the power system 4 into DC power. The first converter 11 is, for example, an AC-DC converter circuit.
The storage element 14 stores DC power output from the first converter 11. The storage element 14 is, for example, a capacitor, a secondary battery, etc. The storage element 14 may be any element that can store the DC power output from the first converter 11.
The second converter 12 converts the DC power stored in the storage element 14 into another DC power corresponding to the electrolytic cell 2, and supplies the DC power after the conversion between the anode 2a and the cathode 2b of the electrolytic cell 2. The second converter 12 is, for example, a DC-DC converter circuit. The second converter 12 includes, for example, multiple conversion circuits 20 that are connected in parallel.
As Illustrated in
One input terminal 20a is connected with a terminal of the storage element 14 at the high potential side. The other input terminal 20b is connected with a terminal of the storage element 14 at the low potential side. As a result, the DC power that is stored in the storage element 14 is input to the conversion circuit 20 via the pair of input terminals 20a and 20b.
The switching elements 21 and 22 include a pair of major terminals and a control terminal. Also, the switching elements 21 and 22 have an on-state and an off-state. The on-state is a state in which a current is caused to flow between the pair of major terminals. The off-state is a state in which the flow of the current between the pair of major terminals is blocked. The switching elements 21 and 22 each switch between the on-state and the off-state according to the voltage between the pair of major terminals and the voltage of the control terminal. The off-state is not limited to a state in which a current completely does not flow between the pair of major terminals, and may be a state in which a faint current within a range that does not affect the operation of the conversion circuit 20 flows between the pair of major terminals.
The switching elements 21 and 22 are, for example, self-commutated semiconductor switching elements such as IGBTs, MOSFETs, etc. However, the switching elements 21 and 22 are not limited thereto, and may be any element that can switch arbitrarily between the on-state and the off-state.
One major terminal of the switching element 21 is electrically connected with the input terminal 20a. The other major terminal of the switching element 21 is electrically connected with one major terminal of the switching element 22. The switching element 22 is connected in series with the switching element 21. The other major terminal of the switching element 22 is electrically connected with the input terminal 20b. The switching elements 21 and 22 are connected in series between the Input terminals 20a and 20b. In other words, the switching element 21 is located between the input terminal 20a and the switching element 22; and the switching element 22 is located between the switching element 21 and the input terminal 20b.
The rectifying element 23 is connected in anti-parallel with the switching element 21. The rectifying element 24 is connected in anti-parallel with the switching element 22. The rectifying elements 23 and 24 are, for example, diodes. The anodes of the rectifying elements 23 and 24 are electrically connected with the major terminals of the switching elements 21 and 22 at the low potential side; and the cathodes of the rectifying elements 23 and 24 are electrically connected with the major terminals of the switching elements 21 and 22 at the high potential side. The directions (the rectifying directions) of the currents flowing in the rectifying elements 23 and 24 are the opposite directions of the directions of the currents flowing in the switching elements 21 and 22.
The capacitor 25 is located between the input terminals 20a and 20b. For example, the capacitor 25 suppresses fluctuation of the DC power input from the storage element 14 to the conversion circuit 20.
One end of the reactor 26 is electrically connected with the connection point of the switching elements 21 and 22. The other end of the reactor 26 is electrically connected with one output terminal 20c. The other output terminal 20d is electrically connected with the input terminal 20b.
Each of the multiple conversion circuits 20 includes the switching elements 21 and 22 and converts DC power by the switching of the switching elements 21 and 22. The conversion circuit 20 is, for example, a buck chopper circuit. For example, the conversion circuit 20 converts the DC power stored in the storage element 14 into another DC power corresponding to the electrolytic cell 2 by the switching of the switching element 21.
The second converter 12 includes the multiple conversion circuits 20 connected in parallel. As a result, it is possible to handle a large DC power while suppressing an increase of the current and/or voltage tolerances required by the switching elements 21 and 22. The conversion circuit 20 includes, for example, the multiple switching elements 21 connected in parallel, the multiple switching elements 22 connected in parallel, the multiple rectifying elements 23 connected in anti-parallel in each of the multiple switching elements 21, and the multiple rectifying elements 24 connected in anti-parallel in each of the multiple switching elements 22. As a result, an increase of the current and/or voltage tolerances required by the switching elements 21 and 22 can be further suppressed.
However, the configuration of the conversion circuit 20 and the configuration of the second converter 12 are not limited to those described above, and may be any configuration that can convert the DC power stored in the storage element 14 into another DC power corresponding to the electrolytic cell 2. For example, it is sufficient to appropriately set the number of the conversion circuits 20 connected in parallel and the number of each of the switching elements 21 and 22 connected in parallel according to the magnitude of the DC power to be handled, etc.
The control device 16 controls the operations of the first and second converters 11 and 12. For example, the control device 16 controls the operation of the second converter 12 by controlling the switching of the switching elements 21 and 22 by generating multiple control signals corresponding respectively to the switching elements 21 and 22 of the multiple conversion circuits 20 and by inputting the control signals to the control terminals of the switching elements 21 and 22.
The control device 16 includes a normal operation mode and a corrosion prevention operation mode. The normal operation mode is a mode when the power system 4 is normal, and controls the operations of the first and second converters 11 and 12 to supply, to the electrolytic cell 2, DC power for performing electrolysis based on the AC power supplied from the power system 4.
For example, the control device 16 receives command values of the direct current and the DC voltage to be supplied to the electrolytic cell 2 from a higher-level controller or the like, and controls the operations of the first and second converters 11 and 12 to output the direct current and the DC voltage corresponding to the received command values. For example, the command values change according to the production amount of the product of the electrolytic cell 2, etc. As a result, the production of the necessary amount of the product by the electrolytic cell 2, etc., can be performed based on the supply of the DC power from the electrolytic cell power supply device 10 (the second converter 12).
The corrosion prevention operation mode is a mode in a power interruption of the power system 4, and controls the operation of the second converter 12 to suppress the generation of a reverse current by supplying, to the electrolytic cell 2, a DC power that is based on the DC power stored in the storage element 14 and is smaller than the DC power supplied to the electrolytic cell 2 in the normal operation mode, wherein the reverse current is a current having the opposite direction of the normal electrolysis inside the electrolytic cell 2. The power supply of the control device 16 in the power interruption of the power system 4 may be supplied from the storage element 14, or may be supplied from another power supply such as a battery, etc. The control device 16 may include, for example, an auxiliary power supply such as a battery or the like for continuing the operation in the power interruption of the power system 4.
The magnitude of the direct current supplied from the second converter 12 to the electrolytic cell 2 in the corrosion prevention operation mode is set to, for example, about 1% (e.g., not less than 0.5% and not more than 5%) of the maximum value of the magnitude of the direct current supplied from the second converter 12 to the electrolytic cell 2 in the normal operation mode. The corrosion prevention operation mode may be, for example, a state in which a DC voltage of a prescribed magnitude is applied between the anode 2a and the cathode 2b of the electrolytic cell 2 while setting the magnitude of the direct current supplied by the electrolytic cell 2 to be as close to zero as possible.
For example, the control device 16 stops the operation of the first converter 11 in the corrosion prevention operation mode. For example, the control device 16 stops the operation of the first converter 11 by stopping the input of the control signal to the first converter 11. The control device 16 stops the operation of the first converter 11 by performing a so-called gate block.
The electrolytic cell power supply device 10 further includes, for example, a measuring instrument that is not illustrated. For example, the measuring instrument measures the alternating current and AC voltage of the power system 4, and inputs the measurement results to the control device 16. In other words, the measuring instrument can be used to detect the power interruption of the power system 4.
The control device 16 detects the power interruption of the power system 4 based on the measurement result of the measuring instrument in the normal operation mode, and switches from the normal operation mode to the corrosion prevention operation mode according to the detection of the power interruption. Then, the control device 16 detects the recovery from the power interruption of the power system 4 based on the measurement result of the measuring instrument in the corrosion prevention operation mode, and switches from the corrosion prevention operation mode to the normal operation mode according to the detection of the recovery from the power interruption.
The detection method of the power interruption of the power system 4 and the detection method of the recovery from the power interruption of the power system 4 of the control device 16 are not limited to those described above. For example, the control device 16 may detect the power interruption and the recovery from the power interruption based on a signal input from a higher-level controller. The detection method of the power interruption of the power system 4 and the detection method of the recovery from the power interruption of the power system 4 of the control device 16 may be any method that can appropriately detect the power interruption and the recovery from the power interruption of the power system 4.
Also, in this specification, “power interruption” is not limited to a drop of the voltage of the power system 4 that continues for not less than a prescribed period, but also includes an instantaneous interruption, an instantaneous voltage drop, etc., in which the voltage of the power system 4 temporarily drops for only a short period of time such as less than one minute, etc.
In the electrolytic cell power supply device 10 according to the embodiment as described above, the control device 16 includes the normal operation mode and the corrosion prevention operation mode, and switches from the normal operation mode to the corrosion prevention operation mode according to the detection of the power interruption.
As a result, in the electrolytic cell power supply device 10, for example, higher complexity of the configuration of the equipment related to the electrolytic cell 2 can be suppressed compared to when a corrosion prevention power supply is prepared separately from the electrolytic cell power supply device 10 and power is supplied from the corrosion prevention power supply to the electrolytic cell 2 when a power interruption occurs, etc. For example, larger equipment, increased costs, etc., can be suppressed. The electrolytic cell power supply device 10 can suppress the generation of a reverse current with a simpler configuration.
Also, in the electrolytic cell power supply device 10, the operation of the first converter 11 is stopped in the corrosion prevention operation mode. As a result, the undesirable consumption of the DC power stored in the storage element 14 by the operation of the first converter 11 can be suppressed. Accordingly, the operation of the corrosion prevention operation mode by the DC power stored in the storage element 14 can be continued for a longer period of time; and degradation of the electrolytic cell 2 due to the generation of the reverse current can be suppressed for a longer period of time.
As illustrated in
In the example, the first converter 11 includes six switching elements 30 having a three-phase full-bridge connection, and six rectifying elements 32 connected in anti-parallel respectively with the six switching elements 30.
The first converter 11 converts the AC power supplied from the power system 4 into DC power by rectifying with the multiple rectifying elements 32. The multiple rectifying elements 32 are, for example, diodes. For example, the first converter 11 converts the AC power supplied from the power system 4 into DC power by a diode bridge circuit.
Also, the first converter 11 converts the DC power stored in the storage element 14 into AC power by the switching of the multiple switching elements 30. Thus, in the example, the first converter 11 has the function of converting the AC power supplied from the power system 4 into DC power and supplying the DC power to the storage element 14, and the function of converting the DC power stored in the storage element 14 into AC power and supplying the AC power to the power system 4. In other words, the first converter 11 has a bidirectional conversion function of converting AC power to DC power and converting DC power to AC power.
In the corrosion prevention operation mode, the control device 16 controls the operation of the first converter 11 to supply only reactive power to the power system 4 based on the DC power stored in the storage element 14.
Thus, in the example, the first converter 11 has a bidirectional conversion function; and in the corrosion prevention operation mode, the control device 16 controls the operation of the first converter 11 to supply only reactive power to the power system 4. As a result, in the example, a contribution can be made to maintain the voltage of the power system 4 when a power interruption occurs in the power system 4.
As described with reference to the first embodiment above, degradation of the electrolytic cell 2 can be suppressed for a longer period of time when the operation of the first converter 11 is stopped in the corrosion prevention operation mode. It is sufficient to appropriately select whether to stop the operation of the first converter 11 or to operate the first converter 11 to supply only reactive power in the corrosion prevention operation mode according to the capacity of the storage element 14, the specifications of the power system 4, etc. For example, the switching between the mode of stopping the operation of the first converter 11 and the mode of operating the first converter 11 to supply only reactive power may be performed based on a signal input from the outside, etc.
As illustrated in
The control device 16 switches from the normal operation mode to the corrosion prevention operation mode according to the detection of the power interruption of the power system 4. When switching to the corrosion prevention operation mode, the control device 16 gradually reduces the magnitude of the DC power supplied to the electrolytic cell 2. For example, the control device 16 gradually reduces the magnitude of the DC power supplied to the electrolytic cell 2 by gradually reducing the command value of the direct current supplied to the electrolytic cell 2 from the level of the normal operation mode to the level of the corrosion prevention operation mode. In other words, the control device 16 gradually reduces the magnitude of the direct current supplied to the electrolytic cell 2.
When operating in the corrosion prevention operation mode, the control device 16 detects the recovery from the power interruption of the power system 4 based on the receiving voltage of the power system 4 measured by the measuring instrument, which is not illustrated. The control device 16 detects the recovery from the power interruption of the power system 4 when the receiving voltage of the power system 4 reaches or exceeds a recovery determination level VL2. For example, the recovery determination level VL2 is set to a larger value than the power interruption determination level VL1. As a result, for example, the undesirable detection of an occurrence of a power interruption immediately after the control device 16 detects the recovery from the power interruption can be suppressed.
The control device 16 switches from the corrosion prevention operation mode to the normal operation mode according to the detection of the recovery from the power Interruption of the power system 4. When switching to the normal operation mode, the control device 16 gradually increases the magnitude of the DC power supplied to the electrolytic cell 2. For example, the control device 16 gradually increases the magnitude of the DC power supplied to the electrolytic cell 2 by gradually increasing the command value of the direct current supplied to the electrolytic cell 2 from the level of the corrosion prevention operation mode to the level of the normal operation mode. In other words, the control device 16 gradually increases the magnitude of the direct current supplied to the electrolytic cell 2.
Thus, in the example, the control device 16 gradually changes the magnitude of the DC power supplied to the electrolytic cell 2 when switching from the normal operation mode to the corrosion prevention operation mode and when switching from the corrosion prevention operation mode to the normal operation mode. As a result, for example, degradation of the electrolytic cell 2 due to an abrupt change of the DC power (the direct current) supplied to the electrolytic cell 2 can be suppressed.
As described above, when gradually changing the magnitude of the DC power supplied to the electrolytic cell 2, the capacity of the storage element 14 (the magnitude of the DC power stored in the storage element 14) is determined according to the consumed energy necessary for gradually changing the magnitude of the DC power.
In
As illustrated in
The emergency generator 40 is a generator for charging the storage element 14 in a power interruption of the power system 4. The power that is generated by the emergency generator 40 is, for example, AC power. The emergency generator 40 is, for example, an AC generator. The emergency generator 40 is, for example, an engine generator that generates power based on a fuel such as gasoline, gas, etc. The startup and shutdown of the emergency generator 40 is controlled by, for example, the control device 16.
The rectifier 42 is a rectifier for performing the pre-charging of the storage element 14 based on the AC power supplied from the power system 4. The rectifier 42 is, for example, a diode bridge circuit. For example, the rectifier 42 performs the pre-charging of the storage element 14 by performing rectification of the AC power supplied from the power system 4, and by supplying the power after rectification to the storage element 14. However, the configuration of the rectifier 42 is not limited to that described above, and may be any configuration that can perform the pre-charging of the storage element 14 based on the AC power supplied from the power system 4.
For example, the rectifier 42 is connected with the power system 4 via the switch 44 and the transformer 48. The switching of the switch 44 is controlled by, for example, the control device 16. For example, when the voltage of the storage element 14 is in an extremely low state such as at the operation start of the electrolytic cell power supply device 10a, etc., the control device 16 engages the switch 44 to charge the storage element 14 via the rectifier 42 to a level at which the first converter 11 and the second converter 12 can operate correctly. For example, after the storage element 14 is charged to a level at which the first converter 11 and the second converter 12 can operate correctly, the control device 16 opens the switch 44 and starts the operations of the first and second converters 11 and 12.
The emergency generator 40 is connected with the storage element 14 via the rectifier 42. The emergency generator 40 charges the storage element 14 via the rectifier 42 by generating AC power, and by supplying the generated AC power to the rectifier 42.
The switch 46 is located between the emergency generator 40 and the rectifier 42. For example, the emergency generator 40 is connected with the storage element 14 via the switch 46 and the rectifier 42. For example, the switching of the switch 46 is controlled by the control device 16.
In the normal operation mode, the control device 16 stops the emergency generator 40 and opens the switch 46. Then, when switching from the normal operation mode to the corrosion prevention operation mode according to the detection of the power interruption of the power system 4, the control device 16 starts the operation of the emergency generator 40 and charges the storage element 14 based on the power generated by the emergency generator 40 in the power interruption of the power system 4 by engaging the switch 46. For example, the control device 16 may detect the voltage of the storage element 14 in the corrosion prevention operation mode, and may charge the storage element 14 based on the power generated by the emergency generator 40 only when the voltage of the storage element 14 decreases.
Thus, in the example, the electrolytic cell power supply device 10a further includes the emergency generator 40. As a result, the operation in the corrosion prevention operation mode can be continued for a longer period of time by using the DC power stored in the storage element 14; and degradation of the electrolytic cell 2 due to the generation of the reverse current can be suppressed for a longer period of time.
For example, it may undesirably take about 40 seconds after starting the emergency generator 40 until a stable output is obtained. In the electrolytic cell power supply device 10a, for example, the capacity of the storage element 14 is set so that the corrosion prevention operation mode can be performed using the DC power stored in the storage element 14 for the startup period of the emergency generator 40. As a result, the necessary capacity of the storage element 14 can be prevented from being excessive. The necessary capacity of the storage element 14 can be suppressed, and a larger storage element 14, increased costs, etc., can be suppressed. The corrosion prevention operation mode can be continued for a long period of time while suppressing the capacity of the storage element 14.
Also, in the example, the electrolytic cell power supply device 10a further includes the rectifier 42; and the emergency generator 40 charges the storage element 14 via the rectifier 42 by supplying the generated AC power to the rectifier 42. Thus, when the power generated by the emergency generator 40 is AC power, the storage element 14 is charged via the rectifier 42 used for the pre-charging. As a result, even when the AC emergency generator 40 is used, the need to further add another rectifier or the like is suppressed, and a higher number of components, additional costs, etc., can be suppressed.
The power that is generated by the emergency generator 40 is not limited to AC power, and may be DC power. The emergency generator 40 may be a DC generator, a storage battery, etc. In such a case, the rectifier 42 is omissible. The electrolytic cell power supply device 10a may not always include the rectifier 42.
As illustrated in
The first current sensor 51 is a sensor configured to detect the direct current supplied from the second converter 12 to the electrolytic cell 2 in the normal operation mode. The electrolytic cell power supply device 10b includes, for example, multiple first current sensors 51 corresponding respectively to the multiple conversion circuits 20. The multiple first current sensors 51 detect the direct current supplied to the electrolytic cell 2 respectively from the multiple conversion circuits 20 in the normal operation mode. The multiple first current sensors 51 input the detection results of the direct currents to the control device 16.
The control device 16 controls the operation of the second converter 12 based on the detection result of the first current sensor 51 in the normal operation mode. For example, the control device 16 controls the operations of the multiple conversion circuits 20 based on the detection results of the multiple first current sensors 51 in the normal operation mode. For example, the control device 16 controls the operations of the multiple conversion circuits 20 so that direct currents corresponding to current command values are output from the multiple conversion circuits 20 based on the detection results of the multiple first current sensors 51.
The second current sensor 52 is a sensor configured to detect the direct current supplied from the second converter 12 to the electrolytic cell 2 in the corrosion prevention operation mode. For example, the second current sensor 52 is located between the second converter 12 and the electrolytic cell 2. In other words, the second current sensor 52 is located between the multiple conversion circuits 20 and the electrolytic cell 2. For example, the second current sensor 52 detects the merged direct current at the parallel connection of the multiple conversion circuits 20. The second current sensor 52 inputs the detection result of the direct current to the control device 16.
In the corrosion prevention operation mode, the control device 16 controls the operation of the second converter 12 based on the detection result of the second current sensor 52. For example, the control device 16 controls the operations of the multiple conversion circuits 20 based on the detection result of the second current sensor 52 in the corrosion prevention operation mode. For example, the control device 16 controls the operations of the multiple conversion circuits 20 so that direct currents corresponding to the current command values are output from the multiple conversion circuits 20 based on the detection result of the second current sensor 52.
Thus, in the example, the control device 16 controls the operation of the second converter 12 based on the detection result of the first current sensor 51 in the normal operation mode, and controls the operation of the second converter 12 based on the detection result of the second current sensor 52 in the corrosion prevention operation mode.
As described above, the direct current that is supplied from the second converter 12 to the electrolytic cell 2 in the corrosion prevention operation mode is a small current that is about 1% of the maximum value of the magnitude of the direct current supplied from the second converter 12 to the electrolytic cell 2 in the normal operation mode. In such a case, when the same current sensor as the current sensor used in the normal operation mode is used, there is a possibility that the magnitude of the direct current supplied from the second converter 12 to the electrolytic cell 2 in the corrosion prevention operation mode cannot be detected appropriately.
Therefore, the electrolytic cell power supply device 10b includes the two types of current sensors of the first current sensor 51 and the second current sensor 52. The second current sensor 52 is, for example, a current sensor that can detect a smaller direct current than the first current sensor 51. As a result, the magnitude of the direct current supplied from the second converter 12 to the electrolytic cell 2 in the corrosion prevention operation mode can be more appropriately detected. By using the detection result of the second current sensor 52, the operation of the second converter 12 in the corrosion prevention operation mode can be more appropriately controlled.
For example, an insufficient direct current supplied from the second converter 12 to the electrolytic cell 2, etc., can be suppressed, and degradation of the electrolytic cell 2 can be more appropriately suppressed. Or, the supply of an excessive direct current can be prevented from increasing the consumption of the DC power stored in the storage element 14 which may undesirably prevent the corrosion prevention operation mode from continuing.
In the example, the multiple first current sensors 51 that correspond respectively to the multiple conversion circuits 20 are included. The first current sensors 51 are not limited thereto; similarly to the second current sensor 52, a configuration may be used in which one first current sensor 51 is located between the second converter 12 and the electrolytic cell 2.
As illustrated in
The multiple current sensors 60 are arranged to correspond respectively to the multiple conversion circuits 20. The multiple current sensors 60 detect the direct currents supplied to the electrolytic cell 2 respectively from the multiple conversion circuits 20. The multiple current sensors 60 input the detection results of the direct currents to the control device 16.
The control device 16 controls the operation of the second converter 12 based on the detection results of the multiple current sensors 60. More specifically, the control device 16 controls the operations of the multiple conversion circuits 20 based on the detection results of the multiple current sensors 60. For example, the control device 16 controls the operations of the multiple conversion circuits 20 so that direct currents corresponding to the current command values are output respectively from the multiple conversion circuits 20 based on the detection results of the multiple current sensors 60.
In other words, the configuration of the electrolytic cell power supply device 10c is the configuration of the electrolytic cell power supply device 10b of the embodiment above in which the second current sensor 52 is omitted, and only the multiple first current sensors 51 are included. In the example, the control device 16 controls the operation of the second converter 12 based on the detection results of the multiple current sensors 60 in the normal operation mode and the corrosion prevention operation mode.
In the electrolytic cell power supply device 10c, the control device 16 operates each of the multiple conversion circuits 20 in the normal operation mode, and operates only a portion of the multiple conversion circuits 20 in the corrosion prevention operation mode. For example, the control device 16 operates each of the multiple conversion circuits 20 connected in parallel in the normal operation mode, and operates only one of the multiple conversion circuits 20 in the corrosion prevention operation mode.
Thus, in the electrolytic cell power supply device 10c, the control device 16 operates only a portion of the multiple conversion circuits 20 in the corrosion prevention operation mode. As a result, in the corrosion prevention operation mode, the current can be concentrated in the portion of the conversion circuit 20 that is operated. Thus, in the corrosion prevention operation mode, by concentrating the current in only a portion of the conversion circuits 20, the value of the current detected by the current sensor 60 can be increased, and even when the same current sensor 60 as the normal operation mode is used, the micro current of the corrosion prevention operation mode can be detected with high accuracy. For example, it is unnecessary to separately provide the second current sensor 52 that has a high detection accuracy, etc. An Increase of components can be suppressed, and the operation of the corrosion prevention operation mode can be realized with a simpler configuration.
FIGS, 8A and 8B schematically Illustrate an example of the timing of the switching of the switching elements 21 provided respectively in the multiple conversion circuits 20. In
As illustrated in
Also, in the normal operation mode as illustrated in
As illustrated in
Thus, in the example, in the normal operation mode, the control device 16 performs a control of shifting the timing of the switching of the switching elements 21 of the multiple conversion circuits 20. As a result, a ripple superimposed onto the output current in the normal operation mode can be reduced,
Also, in the example, the control device 16 performs a control of setting the switching frequencies of the switching elements 21 of a portion of the conversion circuits 20 among the multiple conversion circuits 20 in the corrosion prevention operation mode to be higher than the switching frequencies of the switching elements 21 of the multiple conversion circuits 20 in the normal operation mode. As a result, a ripple superimposed onto the output current also can be reduced in the corrosion prevention operation mode. An excessive increase of a ripple superimposed onto the output current can be suppressed even when the number of the conversion circuits 20 being operated is reduced. For example, a more stable direct current can be supplied to the electrolytic cell 2.
Embodiments may include the following configurations.
An electrolytic cell power supply device causing an electrolytic cell to perform electrolysis by supplying direct current power between an anode and a cathode of the electrolytic cell, the electrolytic cell power supply device comprising:
The electrolytic cell power supply device according to Appendix 1, wherein
The electrolytic cell power supply device according to Appendix 1, wherein
The electrolytic cell power supply device according to any one of Appendixes 1 to 3, wherein
The electrolytic cell power supply device according to any one of Appendixes 1 to 4, further comprising:
The electrolytic cell power supply device according to Appendix 5, further comprising:
The electrolytic cell power supply device according to any one of Appendixes 1 to 6, further comprising:
The electrolytic cell power supply device according to any one of Appendixes 1 to 7, wherein
The electrolytic cell power supply device according to Appendix 8, wherein
Although several embodiments of the invention are described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be carried out in other various forms; and various omissions, substitutions, and modifications can be performed without departing from the spirit of the invention. Such embodiments and their modifications are within the scope and spirit of the invention and are included in the invention described in the claims and their equivalents.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/043119 | 11/22/2022 | WO |
