Power supply device for electrolytic cell
Patent Information
- Application Number
- PCT/JP2025/010192
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-17
- Publication Date
- 2026-09-24
Smart Images
Figure JP2025010192_24092026_PF_FP_ABST
Abstract
Description
Power supply device for electrolytic cells
[0001] Embodiments of the present invention relate to a power supply device for electrolytic cells.
[0002] There is a power supply device for an electrolytic cell that causes the electrolytic cell to perform electrolysis by supplying DC power between the anode and the cathode of the electrolytic cell. The power supply device for an electrolytic cell is connected to an AC power system, converts AC power supplied from the power system into DC power adapted to the electrolytic cell, and supplies the converted DC power between the anode and the cathode of the electrolytic cell. The electrolytic cell produces products such as hydrogen, for example, by performing electrolysis in response to the supply of DC power from the power supply device for the electrolytic cell.
[0003] The power supply device for an electrolytic cell includes a first converter that converts AC power supplied from a power system into DC power, and a second converter that converts the DC power output from the first converter into another DC power adapted to the electrolytic cell. With only the first converter, current cannot be started from 0 V (zero volts), and the minimum DC voltage is determined by the system voltage. Therefore, the power supply device for an electrolytic cell is used in combination with the second converter to enable current startup from 0 V.
[0004] However, in a configuration in which the first converter and the second converter are operated at all times, there is a concern that conversion efficiency when converting AC power into DC power adapted to the electrolytic cell is poor. In other words, in a configuration where the first converter and the second converter are constantly operated, there is a concern that a larger amount of power is required to cause the electrolytic cell to perform electrolysis.
[0005] For this reason, it is desired for power supply devices for electrolytic cells to enable conversion from AC power to DC power adapted to the electrolytic cell with higher efficiency.
[0006] Japanese Unexamined Patent Publication No. 2024-38846
[0007] Embodiments of the present invention provide a power supply device for an electrolytic cell that can convert AC power into DC power adapted to the electrolytic cell with higher efficiency.
[0008] According to an embodiment of the present invention, an electrolytic cell power supply device for causing an electrolytic cell to perform electrolysis by supplying DC power between the anode and cathode of the electrolytic cell, comprising: a first converter that converts AC power to DC power and can change the magnitude of the output DC voltage within a range from a minimum voltage corresponding to the magnitude of the AC voltage of the AC power to a maximum voltage corresponding to the electrolytic cell, and can supply the converted DC power to the electrolytic cell; and a second converter that converts DC power to another DC power and can change the magnitude of the output DC voltage within a range from 0V to the minimum voltage of the first converter, and can supply the converted DC power to the electrolytic cell. The electrolytic cell power supply device is provided, comprising: a control device that controls the operation of power conversion by the first converter and the operation of power conversion by the second converter, wherein when supplying a DC voltage in the range from 0V to the minimum voltage of the first converter to the electrolytic cell, the control device operates the second converter to supply DC power from the second converter to the electrolytic cell, and when supplying a DC voltage in the range from the minimum voltage of the first converter to the maximum voltage of the first converter to the electrolytic cell, the control device operates the first converter and stops the operation of the second converter to supply DC power from the first converter to the electrolytic cell.
[0009] According to embodiments of the present invention, a power supply device for an electrolytic cell is provided that can convert AC power to DC power corresponding to the electrolytic cell with higher efficiency.
[0010] This is a schematic block diagram of a power supply unit for an electrolytic cell according to the first embodiment. Figures 2(a) to 2(c) are schematic block diagrams illustrating an example of the operation of the power supply unit for an electrolytic cell according to the first embodiment. Figures 3(a) to 3(c) are schematic block diagrams illustrating an example of the operation of the power supply unit for an electrolytic cell according to the first embodiment. This is a schematic graph illustrating an example of the characteristics of an electrolytic cell. This is a schematic block diagram of a power supply unit for an electrolytic cell according to the second embodiment. This is a schematic block diagram illustrating a modified version of the power supply unit for an electrolytic cell according to the second embodiment. This is a schematic block diagram illustrating a modified version of the power supply unit for an electrolytic cell according to the second embodiment. This is a schematic block diagram of a power supply unit for an electrolytic cell according to the third embodiment.
[0011] The embodiments will be described below with reference to the drawings. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes of the parts, etc., are not necessarily the same as those of actual objects. Furthermore, even when representing the same part, the dimensions and ratios may be shown differently in different drawings. In this specification and in each drawing, elements similar to those described above are denoted by the same reference numerals, and detailed explanations are omitted as appropriate.
[0012] (First Embodiment) Figure 1 is a schematic block diagram of a power supply device for an electrolytic cell according to the first embodiment. As shown in Figure 1, the power supply device 10 for an electrolytic cell comprises a first converter 11, a second converter 12, and a control device 14. The power supply device 10 for an electrolytic cell is used in an electrolytic cell 2. The electrolytic cell 2 has an anode 2a and a cathode 2b. The power supply device 10 for an electrolytic cell supplies DC power between the anode 2a and the cathode 2b of the electrolytic cell 2, thereby causing the electrolytic cell 2 to perform electrolysis.
[0013] The electrolytic cell 2 generates products such as hydrogen by performing electrolysis in response to the supply of DC power from the electrolytic cell power supply device 10. The electrolytic cell 2 may further include, for example, an ion exchange membrane (diaphragm) placed between the anode 2a and the cathode 2b. The configuration of the electrolytic cell 2 may be any configuration that has at least an anode 2a and a cathode 2b and is capable of performing electrolysis of an electrolyte or the like by supplying DC power between the anode 2a and the cathode 2b.
[0014] The electrolytic cell power supply unit 10 is connected to the electrolytic cell 2 and also to the power system 4. The power system 4 is an AC power system. The electrolytic cell power supply unit 10 is connected to the power system 4 via, for example, a transformer 6. 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, but may also be single-phase AC power, etc.
[0015] The first converter 11 is connected to the power system 4. The first converter 11 is connected to the power system 4 via, for example, a transformer 6. The first converter 11 converts the AC power supplied from the power system 4 into DC power. The first converter 11 makes the converted DC power available for supply to the electrolytic cell 2. The AC power supplied to the first converter 11 is not limited to the power system 4, but may also be supplied from, for example, an AC power source or an AC generator.
[0016] The first converter 11 converts AC power to DC power and can change the magnitude of the DC voltage it outputs within a range from a minimum voltage corresponding to the magnitude of the AC voltage of the power system 4 to a maximum voltage corresponding to the electrolytic cell 2. The minimum voltage of the first converter 11 is set, for example, according to the maximum value of the AC voltage of the power system 4. The maximum voltage of the first converter 11 is set, for example, higher than the minimum voltage and to a magnitude that can output the voltage required by the electrolytic cell 2.
[0017] The first converter 11 is, for example, a converter circuit. The configuration of the first converter 11 can be any configuration that converts AC power to DC power and can also change the magnitude of the DC voltage output as described above.
[0018] The second converter 12 receives DC power and converts it into another type of DC power. The second converter 12 receives DC power from, for example, the first converter 11. The first converter 11 makes the converted DC power available for supply to the electrolytic cell 2 and also for supply to the second converter 12. The second converter 12 converts the DC power supplied from the first converter 11 into another type of DC power. The second converter 12 makes the converted DC power available for supply to the electrolytic cell 2.
[0019] The second converter 12 converts DC power to another DC power and can change the magnitude of the DC voltage it outputs within a range from 0V (zero volts) to the lowest voltage of the first converter 11. The second converter 12 is, for example, a chopper circuit. The configuration of the second converter 12 can be any configuration that can convert DC power to another DC power and change the magnitude of the DC voltage it outputs as described above. The second converter 12 may be, for example, a single chopper circuit or a double chopper circuit.
[0020] The control device 14 controls the operation of the power conversion by the first converter 11, as well as the operation of the power conversion by the second converter 12.
[0021] When the control device 14 supplies a DC voltage to the electrolytic cell 2 in the range from 0V to the lowest voltage of the first converter 11, it operates the second converter 12, thereby supplying DC power from the second converter 12 to the electrolytic cell 2.
[0022] When the control device 14 supplies a DC voltage in the range from 0V to the lowest voltage of the first converter 11 to the electrolytic cell 2, for example, it operates the first converter 11 and the second converter 12, supplies DC power from the first converter 11 to the second converter 12, and has the second converter 12 convert the DC power supplied from the first converter 11 to another DC power, thereby supplying DC power from the second converter 12 to the electrolytic cell 2.
[0023] When the control device 14 supplies a DC voltage to the electrolytic cell 2 within the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11, it operates the first converter 11 and stops the operation of the second converter 12, thereby supplying DC power from the first converter 11 to the electrolytic cell 2.
[0024] The electrolytic cell power supply unit 10 further includes, for example, switches 21 to 24 and voltage detectors 31 and 32.
[0025] Switches 21 and 22 are installed between the first converter 11 and the electrolytic cell 2, and switch between a state in which the first converter 11 and the electrolytic cell 2 are connected and a state in which the first converter 11 and the electrolytic cell 2 are disconnected. More specifically, the state in which the first converter 11 and the electrolytic cell 2 are connected is the state in which the pair of DC output terminals of the first converter 11 are connected to the anode 2a and cathode 2b of the electrolytic cell 2. In other words, the state in which the first converter 11 and the electrolytic cell 2 are disconnected is the state in which the electrical connection between the first converter 11 and the electrolytic cell 2 is released. Switches 21 and 22, for example, connect the first converter 11 and the electrolytic cell 2 when they are turned on, and disconnect the first converter 11 and the electrolytic cell 2 when they are turned off.
[0026] Switches 23 and 24 are installed between the second converter 12 and the electrolytic cell 2, and switch between a state in which the second converter 12 and the electrolytic cell 2 are connected and a state in which the second converter 12 and the electrolytic cell 2 are disconnected. More specifically, the state in which the second converter 12 and the electrolytic cell 2 are connected is the state in which the pair of DC output terminals of the second converter 12 are connected to the anode 2a and cathode 2b of the electrolytic cell 2. In other words, the state in which the second converter 12 and the electrolytic cell 2 are disconnected is the state in which the electrical connection between the second converter 12 and the electrolytic cell 2 is released. Switches 23 and 24, for example, connect the second converter 12 and the electrolytic cell 2 when they are turned on, and disconnect the second converter 12 and the electrolytic cell 2 when they are turned off.
[0027] The second converter 12 is provided, for example, between the first converter 11 and the electrolytic cell 2. In other words, the second converter 12 is provided in parallel with the path connecting the first converter 11 and the electrolytic cell 2 via switches 21 and 22.
[0028] One end of switches 23 and 24 is connected to the second converter 12. More specifically, one end of switch 23 is connected to one DC output terminal of the second converter 12, and one end of switch 24 is connected to the other DC output terminal of the second converter 12. The other ends of switches 23 and 24 are connected in the path between switches 21 and 22 and the electrolytic cell 2. In other words, the other ends of switches 23 and 24 are connected to the electrolytic cell 2 at a position closer to the electrolytic cell 2 than switches 21 and 22. More specifically, the other end of switch 23 is connected to the anode 2a of the electrolytic cell 2 at a position closer to the electrolytic cell 2 than switch 21, and the other end of switch 24 is connected to the cathode 2b of the electrolytic cell 2 at a position closer to the electrolytic cell 2 than switch 22.
[0029] The control device 14 controls the operation of the first converter 11 and the second converter 12, and also controls the switching between the closed and open states of the switches 21 to 24. In other words, the control device 14 controls the switching between the state in which the first converter 11 and the electrolytic cell 2 are connected and the state in which the first converter 11 and the electrolytic cell 2 are disconnected by the switches 21 and 22, and also controls the switching between the state in which the second converter 12 and the electrolytic cell 2 are connected and the state in which the second converter 12 and the electrolytic cell 2 are disconnected by the switches 23 and 24.
[0030] When supplying a DC voltage to the electrolytic cell 2 in the range from 0V to the lowest voltage of the first converter 11, the control device 14 switches switches 21 and 22 to disconnect the first converter 11 and the electrolytic cell 2, and switches switches 23 and 24 to connect the second converter 12 and the electrolytic cell 2.
[0031] This allows the supply of DC power output from the first converter 11 to the electrolytic cell 2 to be suppressed by switches 21 and 22, while the DC power output from the first converter 11 is supplied to the second converter 12, and the DC power output from the second converter 12 is supplied to the electrolytic cell 2 via switches 23 and 24. Therefore, DC power in the range of DC voltage from 0V output from the second converter 12 to the lowest voltage of the first converter 11 can be supplied to the electrolytic cell 2.
[0032] Then, when the control device 14 supplies a DC voltage to the electrolytic cell 2 within the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11, it switches switches 21 and 22 to connect the first converter 11 and the electrolytic cell 2, and switches switches 23 and 24 to disconnect the second converter 12 and the electrolytic cell 2.
[0033] This allows DC power in the range of DC voltage from the lowest voltage to the highest voltage output from the first converter 11 to be supplied to the electrolytic cell 2 via switches 21 and 22. In addition, switches 23 and 24 can prevent the DC power output from the first converter 11 from being input to the second converter 12.
[0034] The voltage detector 31 detects the magnitude of the DC voltage output from the first converter 11 and inputs the detected value of the DC voltage magnitude to the control device 14. The voltage detector 32 detects the magnitude of the DC voltage output from the second converter 12 and inputs the detected value of the DC voltage magnitude to the control device 14.
[0035] The control device 14 controls the operation of the first converter 11 and the second converter 12, and the switching between the closed and open states of the switches 21 to 24, based on the detected magnitude of the DC voltage input from the voltage detectors 31 and 32.
[0036] Figures 2(a) to 2(c) are block diagrams schematically illustrating an example of the operation of the electrolytic cell power supply device according to the first embodiment. Figures 2(a) to 2(c) schematically illustrate an example of the operation of the electrolytic cell power supply device 10 when it is started up. Note that, for convenience, only a part of the electrolytic cell power supply device 10 is shown in Figures 2(a) to 2(c).
[0037] As shown in Figure 2(a), when the control device 14 starts the electrolytic cell power supply device 10, it first switches switches 21 and 22 to disconnect the first converter 11 from the electrolytic cell 2, and then switches switches 23 and 24 to connect the second converter 12 to the electrolytic cell 2, thereby operating the first converter 11 and supplying DC power from the first converter 11 to the second converter 12. In this case, the control device 14 controls the operation of the first converter 11, for example, to output the lowest voltage.
[0038] After the control device 14 starts supplying DC power from the first converter 11 to the second converter 12, it operates the second converter 12 to start supplying DC power from the second converter 12 to the electrolytic cell 2. In this case, the control device 14 controls the operation of the second converter 12 so that, for example, the magnitude of the DC voltage supplied to the electrolytic cell 2 is gradually increased from 0V to the lowest voltage of the first converter 11.
[0039] The control device 14 gradually increases the magnitude of the DC voltage output from the second converter 12 and, based on the detected values of the voltage detectors 31 and 32, determines whether the difference between the magnitude of the DC voltage output from the first converter 11 and the magnitude of the DC voltage output from the second converter 12 has fallen below a predetermined value. In other words, the control device 14 determines whether the magnitude of the DC voltage output from the second converter 12 has become substantially the same as the magnitude of the DC voltage output from the first converter 11. For example, the control device 14 determines whether the magnitudes of the DC voltage output from the first converter 11 and the DC voltage output from the second converter 12 have each reached the minimum voltage of the first converter 11.
[0040] As shown in Figure 2(b), the control device 14 switches the switches 21 and 22 to connect the first converter 11 and the electrolytic cell 2 when the difference between the magnitude of the DC voltage output from the first converter 11 and the magnitude of the DC voltage output from the second converter 12 falls below a predetermined value. In other words, the control device 14 switches the switches 21 and 22 to connect the first converter 11 and the electrolytic cell 2 when the magnitude of the DC voltage output from the second converter 12 becomes substantially the same as the magnitude of the DC voltage output from the first converter 11.
[0041] The control device 14 switches the switches 21 and 22 to connect the first converter 11 and the electrolytic cell 2, starts supplying DC power from the first converter 11 to the electrolytic cell 2, and then gradually reduces the magnitude of the voltage (current) output from the second converter 12.
[0042] As shown in FIG. 2(c), after setting the magnitude of the voltage (current) output from the second converter 12 to zero and stopping the operation of the second converter 12, the control device 14 switches the switches 23 and 24 to a state in which the second converter 12 and the electrolyzer 2 are disconnected.
[0043] After stopping the operation of the second converter 12 and switching the switches 23 and 24 to a state in which the second converter 12 and the electrolyzer 2 are disconnected, the control device 14 gradually increases the magnitude of the DC voltage output from the first converter 11 until the rated current flows through the electrolyzer 2. In other words, the maximum voltage magnitude of the first converter 11 is set to a magnitude that allows a rated current to flow through the electrolyzer 2.
[0044] For example, the control device 14 controls the operation of the first converter 11 so that the rated current flows through the electrolyzer 2. Thereby, the power supply device 10 for an electrolyzer can be activated to cause the electrolyzer 2 to produce a product.
[0045] FIGS. 3(a) to 3(c) are block diagrams schematically illustrating an example of the operation of the power supply device for an electrolyzer according to the first embodiment. FIGS. 3(a) to 3(c) schematically illustrate an example of the operation when the power supply device 10 for an electrolyzer is stopped. Note that, similarly to FIGS. 2(a) to 2(c), in FIGS. 3(a) to 3(c), only a part of the power supply device 10 for an electrolyzer is illustrated for convenience.
[0046] As shown in FIG. 3(a), when stopping the power supply device 10 for an electrolyzer, the control device 14 first switches the switches 21 and 22 to a state where the first converter 11 and the electrolyzer 2 are connected, and switches the switches 23 and 24 to a state where the second converter 12 and the electrolyzer 2 are disconnected, and controls the operation of the first converter 11 to gradually reduce the magnitude of the DC voltage output from the first converter 11 to the minimum voltage of the first converter 11.
[0047] As shown in FIG. 3(b), after reducing the magnitude of the DC voltage output from the first converter 11 to the minimum voltage of the first converter 11, the control device 14 switches the switches 23 and 24 to a state where the second converter 12 and the electrolyzer 2 are connected.
[0048] After switching the switches 23 and 24 to a state where the second converter 12 and the electrolytic cell 2 are connected, the control device 14 starts the operation of the second converter 12, and controls the operation of the second converter 12 to gradually increase the magnitude of the DC voltage output from the second converter 12 from 0V to the minimum voltage of the first converter 11.
[0049] As shown in FIG. 3(c), in response to the difference between the magnitude of the DC voltage output from the first converter 11 and the magnitude of the DC voltage output from the second converter 12 becoming equal to or less than a predetermined value, the control device 14 switches the switches 21 and 22 to a state where the first converter 11 and the electrolytic cell 2 are disconnected.
[0050] After switching the switches 21 and 22 to a state where the first converter 11 and the electrolytic cell 2 are disconnected, the control device 14 controls the operation of the second converter 12 to gradually decrease the magnitude of the DC voltage output from the second converter 12 from the minimum voltage of the first converter 11 to 0V. After decreasing the magnitude of the DC voltage output from the second converter 12 to 0V, the control device 14 stops the operation of the second converter 12 and also stops the operation of the first converter 11. Thereby, the power supply device 10 for an electrolytic cell can be stopped.
[0051] As described above, in the power supply device 10 for an electrolytic cell according to the present embodiment, when the control device 14 supplies a DC voltage in a range from the minimum voltage of the first converter 11 to the maximum voltage of the first converter 11 to the electrolytic cell 2, the control device 14 operates the first converter 11 and stops the operation of the second converter 12, thereby supplying DC power from the first converter 11 to the electrolytic cell 2.
[0052] Thereby, in the power supply device 10 for an electrolytic cell according to the present embodiment, compared with a configuration in which the first converter 11 and the second converter 12 are constantly operated, power consumption associated with the operation of the second converter 12 can be suppressed. In other words, the power required for causing the electrolytic cell 2 to perform electrolysis can be reduced. Therefore, in the power supply device 10 for an electrolytic cell according to the present embodiment, while enabling current rise from 0V, conversion from AC power to DC power adapted to the electrolytic cell 2 can be performed with higher efficiency.
[0053] Figure 4 is a schematic graph illustrating an example of the characteristics of an electrolytic cell. As shown in Figure 4, the electrolytic cell 2 has the characteristic that, for example, when a current of about 10-20% is passed between the anode 2a and cathode 2b, the voltage between the anode 2a and cathode 2b saturates.
[0054] The electrolytic cell power supply unit 10 sets the minimum voltage of the first converter 11 to match the voltage between the anode 2a and cathode 2b of the electrolytic cell 2 as it begins to saturate (for example, Vsat in Figure 4).
[0055] The electrolytic cell power supply unit 10 sets the minimum voltage of the first converter 11 in this way, thereby operating the second converter 12 during the power-saving section until the voltage saturates, and then stopping the operation of the second converter 12 during the subsequent section where power is required, and supplying power to the electrolytic cell 2 using only the first converter 11.
[0056] This allows the second converter 12 to be operated only in power-saving sections, thereby reducing the capacity required for the second converter 12. As a result, the second converter 12 can be made smaller compared to a configuration in which the first converter 11 and the second converter 12 are always in operation. For example, the electrolytic cell power supply unit 10 can be made more efficient compared to a configuration in which the first converter 11 and the second converter 12 are always in operation.
[0057] (Second Embodiment) Figure 5 is a schematic block diagram showing a power supply device for an electrolytic cell according to the second embodiment. As shown in Figure 5, the power supply device for an electrolytic cell 10a further comprises a third converter 13. Components that are substantially the same in function and configuration as those in the above embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.
[0058] The third converter 13 is connected to the power system 4. The third converter 13 is connected to the power system 4 via, for example, a transformer 7. The third converter 13 converts the AC power supplied from the power system 4 into DC power corresponding to the second converter 12. The third converter 13 supplies the converted DC power to the second converter 12. In this example, the second converter 12 converts the DC power supplied from the third converter 13 into another DC power.
[0059] The magnitude of the DC voltage supplied from the third converter 13 to the second converter 12 is set, for example, according to the minimum voltage of the first converter 11. The magnitude of the DC voltage supplied from the third converter 13 to the second converter 12 is substantially the same as, for example, the minimum voltage of the first converter 11.
[0060] The third converter 13 is, for example, a converter using a rectifying element such as a diode. The third converter 13 is, for example, a converter using a diode bridge circuit. The third converter 13 may also be, for example, a converter using a thyristor or a converter using a switching element such as an IGBT. The configuration of the third converter 13 may be any configuration that can convert AC power supplied from the power system 4 into DC power corresponding to the second converter 12.
[0061] Thus, the configuration for supplying DC power to the second converter 12 is not limited to supplying it from the first converter 11, but may also be a configuration in which it is supplied from a third converter 13 separate from the first converter 11.
[0062] The third converter 13 only needs to supply DC power to the second converter 12, and can therefore be a smaller-capacity converter compared to the first converter 11, which is responsible for supplying the rated current to the electrolytic cell 2. Furthermore, in a configuration where DC power is supplied from the third converter 13 to the second converter 12, the operation of the first converter 11 can be stopped when supplying DC power from the second converter 12 to the electrolytic cell 2. For this reason, a configuration where DC power is supplied from the third converter 13 to the second converter 12 can reduce the power required when supplying DC power from the second converter 12 to the electrolytic cell 2, compared to a configuration where DC power is supplied from the first converter 11 to the second converter 12, thus achieving higher efficiency.
[0063] On the other hand, if the configuration is such that DC power is supplied from the first converter 11 to the second converter 12, for example, compared to a configuration in which DC power is supplied from the third converter 13 to the second converter 12, the increase in the number of components can be suppressed, and the device can be made smaller. For example, the manufacturing cost of the device can be reduced.
[0064] Furthermore, the configuration for supplying DC power to the second converter 12 is not limited to the above, and any configuration that can appropriately supply DC power to the second converter 12 is acceptable.
[0065] Figure 6 is a schematic block diagram showing a modified example of the electrolytic cell power supply unit according to the second embodiment. As shown in Figure 6, in the electrolytic cell power supply unit 10b, the transformers 6 and 7 are replaced with a three-winding transformer 8. Thus, the configuration of connecting the first converter 11 and the third converter 13 to the power system 4 is not limited to a configuration in which they are connected to the power system 4 via separate transformers 6 and 7, but may also be a configuration in which they are connected to the power system 4 via the three-winding transformer 8.
[0066] Figure 7 is a schematic block diagram showing a modified example of the electrolytic cell power supply device according to the second embodiment. As shown in Figure 7, in the electrolytic cell power supply device 10c, the third converter 13 is connected to the secondary side of the transformer 6 together with the first converter 11, and is therefore connected to the power system 4 via the transformer 6.
[0067] Thus, the configuration in which the first converter 11 and the third converter 13 are connected to the power system 4 may also be configured by connecting each of the first converter 11 and the third converter 13 to the secondary side of the same transformer 6, thereby connecting them to the power system 4 via the same transformer 6.
[0068] The configuration in which the first converter 11 and the third converter 13 are connected to the power system 4 is not limited to the above, and any configuration that allows the first converter 11 and the third converter 13 to be appropriately connected to the power system 4 is acceptable.
[0069] Furthermore, the power system to which the third converter 13 is connected may be, for example, a different power system from the power system 4 to which the first converter 11 is connected. The configuration for supplying AC power to the third converter 13 is not limited to the above, and may be any configuration that can appropriately supply AC power to the third converter 13. Similar to the first converter 11, the AC power supplied to the third converter 13 is not limited to the power system 4, but may be supplied from, for example, an AC power source or an AC generator.
[0070] (Third Embodiment) Figure 8 is a schematic block diagram showing a power supply device for an electrolytic cell according to the third embodiment. As shown in Figure 8, the power supply device 10d for the electrolytic cell further includes rectifier elements 41 and 42. On the other hand, the switches 23 and 24 are omitted in the power supply device 10d for the electrolytic cell.
[0071] In the electrolytic cell power supply unit 10d, the first converter 11 is connected to the electrolytic cell 2 via switches 21 and 22, and the second converter 12 is also connected to the electrolytic cell 2 via switches 21 and 22. One DC output terminal of the second converter 12 is connected between one DC output terminal of the first converter 11 and switch 21. The other DC output terminal of the second converter 12 is connected between the other DC output terminal of the first converter 11 and switch 22.
[0072] The rectifier element 41 is provided between the connection point between the DC output terminal of the first converter 11 and the DC output terminal of the second converter 11, and the DC output terminal of the first converter 11. The rectifier element 41 allows current to flow from the first converter 11 toward the electrolytic cell 2, and suppresses current flow from the second converter 12 toward the first converter 11. This prevents, for example, the current output from the second converter 12 from flowing into the first converter 11 when DC power is supplied from the second converter 12 to the electrolytic cell 2 while the operation of the first converter 11 is stopped.
[0073] The rectifier element 42 is provided between the connection point between the DC output terminal of the first converter 11 and the DC output terminal of the second converter 11, and the DC output terminal of the second converter 12. The rectifier element 42 allows current to flow from the second converter 12 toward the electrolytic cell 2, while suppressing current flow from the first converter 11 toward the second converter 12. This prevents, for example, the current output from the first converter 11 from flowing to the second converter 12 when DC power is supplied from the first converter 11 to the electrolytic cell 2 while the operation of the second converter 12 is stopped.
[0074] As a result, in the electrolytic cell power supply device 10d, similar to the embodiments described above, when supplying a DC voltage in the range from 0V to the lowest voltage of the first converter 11 to the electrolytic cell 2, the second converter 12 is operated to supply DC power to the electrolytic cell 2 from the second converter 12. When supplying a DC voltage in the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11 to the electrolytic cell 2, the first converter 11 is operated and the operation of the second converter 12 is stopped, thereby supplying DC power to the electrolytic cell 2 from the first converter 11. Note that in the electrolytic cell power supply device 10d, the switches 21 and 22 are provided as needed and can be omitted.
[0075] Thus, the configuration for supplying a DC voltage in the range from 0V to the lowest voltage of the first converter 11 from the second converter 12 to the electrolytic cell 2, and a DC voltage in the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11 from the first converter 11 to the electrolytic cell 2, is not limited to a configuration that is performed by switching the closed and open states of switches 21 to 24, but may also be performed by rectifier elements 41 and 42.
[0076] The rectifier elements 41 and 42 are, for example, reverse current prevention diodes. Depending on the configuration of the second converter 12, even when DC power is supplied from the first converter 11 to the electrolytic cell 2 with the operation of the second converter 12 stopped, the current output from the first converter 11 may not flow to the second converter 12. In this case, the rectifier element 42 can be omitted.
[0077] The configuration for supplying DC voltages in the range from 0V to the lowest voltage of the first converter 11 from the second converter 12 to the electrolytic cell 2, and DC voltages in the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11 from the first converter 11 to the electrolytic cell 2, is not limited to the above, and any configuration that can appropriately supply DC voltages in each range to the electrolytic cell 2 is acceptable. For example, it may be configured by combining any of the switches 21 to 24 and the rectifier elements 41 and 42.
[0078] For example, as shown in Figure 1, when supplying DC power from the first converter 11 to the second converter 12, switches 21 and 22 are necessary to prevent the DC power output from the first converter 11 from being supplied to the electrolytic cell 2 when the second converter 12 supplies a DC voltage in the range from 0V to the lowest voltage of the first converter 11 to the electrolytic cell 2.
[0079] Thus, the configuration for supplying a DC voltage in the range from 0V to the lowest voltage of the first converter 11 from the second converter 12 to the electrolytic cell 2, and supplying a DC voltage in the range from the lowest voltage of the first converter 11 to the highest voltage of the first converter 11 from the first converter 11 to the electrolytic cell 2, can be appropriately set according to the configuration for supplying DC power to the second converter 12, etc.
[0080] This embodiment includes the following aspects: (Note 1) A power supply device for an electrolytic cell that causes the electrolytic cell to perform electrolysis by supplying DC power between the anode and cathode of the electrolytic cell, comprising: a first converter that converts AC power to DC power and can change the magnitude of the output DC voltage in a range from a minimum voltage corresponding to the magnitude of the AC voltage of the AC power to a maximum voltage corresponding to the electrolytic cell, and can supply the converted DC power to the electrolytic cell; a second converter that converts DC power to another DC power and can change the magnitude of the output DC voltage in a range from 0V to the minimum voltage of the first converter, and can supply the converted DC power to the electrolytic cell; and a control device that controls the operation of power conversion by the first converter and controls the operation of power conversion by the second converter, The control device supplies DC power to the electrolytic cell from the second converter by operating the second converter when supplying a DC voltage in the range from 0V to the lowest voltage of the first converter to the electrolytic cell, and by operating the first converter and stopping the operation of the second converter when supplying a DC voltage in the range from the lowest voltage of the first converter to the highest voltage of the first converter to the electrolytic cell.
[0081] (Note 2) The power supply device for an electrolytic cell according to Note 1, wherein the first converter is capable of supplying the converted DC power to the electrolytic cell and also to the second converter, and the second converter converts the DC power supplied from the first converter into another DC power.
[0082] (Note 3) The electrolytic cell power supply device according to Note 2, further comprising a switch for switching between a state in which the first converter and the electrolytic cell are connected and a state in which the first converter and the electrolytic cell are disconnected, wherein the control device controls the operation of the first converter and the second converter and controls the switching of the switch, and when supplying a DC voltage in the range from 0V to the minimum voltage of the first converter to the electrolytic cell, the switch switches to a state in which the first converter and the electrolytic cell are disconnected, and when supplying a DC voltage in the range from the minimum voltage of the first converter to the maximum voltage of the first converter to the electrolytic cell, the switch switches to a state in which the first converter and the electrolytic cell are connected.
[0083] (Note 4) The electrolytic cell power supply device according to Note 1, further comprising a third converter that converts AC power into DC power corresponding to the second converter and supplies the converted DC power to the second converter, wherein the second converter converts the DC power supplied from the third converter into another DC power.
[0084] (Note 5) The electrolytic cell power supply device according to Note 4, further comprising a rectifier element that allows the flow of current from the first converter toward the electrolytic cell and suppresses the flow of current from the second converter toward the first converter.
[0085] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention and in the scope of the invention and its equivalents as described in the claims.
[0086] 2... Electrolytic cell, 2a... Anode, 2a... Cathode, 4... Power system, 6, 7... Transformer, 8... Three-winding transformer, 10, 10a-10d... Power supply unit for electrolytic cell, 11... First converter, 12... Second converter, 13... Third converter, 14... Control device, 21-24... Switch, 31, 32... Voltage detector, 41, 42... Rectifier element
Claims
1. An electrolytic cell power supply device for causing an electrolytic cell to perform electrolysis by supplying DC power between the anode and cathode of the electrolytic cell, comprising: a first converter that converts AC power to DC power and can change the magnitude of the output DC voltage within a range from a minimum voltage corresponding to the magnitude of the AC voltage of the AC power to a maximum voltage corresponding to the electrolytic cell, and can supply the converted DC power to the electrolytic cell; a second converter that converts DC power to another DC power and can change the magnitude of the output DC voltage within a range from 0V to the minimum voltage of the first converter, and can supply the converted DC power to the electrolytic cell; and a control device that controls the operation of power conversion by the first converter and controls the operation of power conversion by the second converter. The control device supplies DC power to the electrolytic cell from the second converter by operating the second converter when supplying a DC voltage in the range from 0V to the lowest voltage of the first converter to the electrolytic cell, and by operating the first converter and stopping the operation of the second converter when supplying a DC voltage in the range from the lowest voltage of the first converter to the highest voltage of the first converter to the electrolytic cell.
2. The electrolytic cell power supply device according to claim 1, wherein the first converter is capable of supplying the converted DC power to the electrolytic cell and also to the second converter, and the second converter converts the DC power supplied from the first converter into another DC power.
3. The electrolytic cell power supply device according to claim 2, further comprising a switch for switching between a state in which the first converter and the electrolytic cell are connected and a state in which the first converter and the electrolytic cell are disconnected, wherein the control device controls the operation of the first converter and the second converter and controls the switching of the switch, and when supplying a DC voltage in the range from 0V to the minimum voltage of the first converter to the electrolytic cell, the switch switches to a state in which the first converter and the electrolytic cell are disconnected, and when supplying a DC voltage in the range from the minimum voltage of the first converter to the maximum voltage of the first converter to the electrolytic cell, the switch switches to a state in which the first converter and the electrolytic cell are connected.
4. The electrolytic cell power supply device according to claim 1, further comprising a third converter that converts AC power to DC power corresponding to the second converter and supplies the converted DC power to the second converter, wherein the second converter converts the DC power supplied from the third converter to another DC power.
5. The electrolytic cell power supply device according to claim 4, further comprising a rectifier element that allows the flow of current from the first converter toward the electrolytic cell and suppresses the flow of current from the second converter toward the first converter.