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CN-122003807-A - Method for starting an electrolytic power supply device with parallel converters and a simplified pre-charging unit

CN122003807ACN 122003807 ACN122003807 ACN 122003807ACN-122003807-A

Abstract

The application relates to a method for starting an electrical power supply unit (10) having a first power converter (22), a second power converter (24) and a rectifying unit (26) and being arranged for supplying electrical energy from an AC power grid (12) to a DC Connection (DCA), wherein at least one DC connection unit (14, 15, 16) is connected at the DC Connection (DCA) of the power supply unit (10) and the AC power grid (12) is connected at the AC Connection (ACA) of the power supply unit (10). The method comprises the steps of pre-charging a first DC intermediate circuit of a first power converter and a second DC intermediate circuit of a second power converter (22 and 24) from an AC grid (12) via an AC pre-charging circuit (18), and building an AC island grid by means of the second power converter (24), wherein during building the AC island grid electrical energy is supplied from the AC island grid to a DC Connection (DCA) via a rectifying unit (26). The application also relates to an electrical power supply unit (10) and an electrolysis power supply arrangement (40).

Inventors

  • C. Halfert

Assignees

  • 艾思玛太阳能技术股份公司

Dates

Publication Date
20260508
Application Date
20241008
Priority Date
20231012

Claims (20)

  1. 1. A method for starting an electrical power supply unit (10) having a first power converter (22), a second power converter (24) and a rectifying unit (26) and being arranged for supplying electrical energy from an AC power grid (12) to a DC Connection (DCA), wherein at least one DC connection unit (14, 15, 16) is connected at the DC Connection (DCA) of the power supply unit (10) and the AC power grid (12) is connected at an AC Connection (ACA) of the power supply unit (10), wherein the method comprises: -pre-charging a first DC intermediate circuit of the first power converter (22) and a second DC intermediate circuit of the second power converter (24) from the AC power grid (12) via an AC pre-charging circuit (18), -Building an AC island grid by means of the second power converter (24), wherein during building the AC island grid, electrical energy is supplied from the AC island grid to the DC Connection (DCA) via the rectifying unit (26).
  2. 2. The method of claim 1, wherein the DC side of the first power converter (22) is connected with the DC side of the second power converter (24) prior to pre-charging the first DC intermediate circuit.
  3. 3. Method according to claim 1 or 2, wherein after pre-charging the second intermediate circuit, the AC side of the second power converter (24) is connected with the AC side of the rectifying unit (26).
  4. 4. The method according to any of the preceding claims, wherein during construction of the AC island grid, AC voltage is regulated and stepped up by the second power converter (24) on its AC side.
  5. 5. The method according to any of the preceding claims, wherein the second power converter (24) is supplied with electrical energy from the first power converter (22) on the DC side during construction of the AC island grid.
  6. 6. The method according to any of the preceding claims, wherein the at least one DC connection unit (14, 16) is pre-charged via the DC Connection (DCA) during construction of the AC island grid.
  7. 7. Method according to any of the preceding claims, wherein after construction of the AC island grid the first power converter (22) is connected on the DC side with the DC Connection (DCA) for supplying electrical energy from the AC grid (12) to the DC Connection (DCA).
  8. 8. Method according to any of the preceding claims, wherein after construction of the AC island grid the second power converter (24) is connected on the DC side with the DC Connection (DCA) and on the AC side with the AC Connection (ACA) for supplying electrical energy from the AC grid (12) to the DC Connection (DCA).
  9. 9. The method according to any of the preceding claims, wherein the rectifying unit (26) comprises a passive rectifier and/or a switched-mode AC/DC converter.
  10. 10. Method according to claim 9, wherein, after construction of the island grid, a switched-mode AC/DC converter of the rectifying unit (26) is connected on the AC side with the AC Connection (ACA) and on the DC side with the DC Connection (DCA) for supplying electrical energy from the AC grid (12) to the DC Connection (DCA).
  11. 11. Method according to any of claims 7 to 10, wherein after construction of the island grid, electrical energy is supplied from the AC grid (12) via the DC link (DCA) to the at least one DC link unit (14) and/or at least one further DC link unit (14), wherein electrical energy is supplied via the first power converter (22), second power converter (24) and/or the switching AC/DC converter.
  12. 12. The method according to any of the preceding claims, wherein the at least one DC connection unit (14) is designed as an electrolytic cell, which is pre-charged via the DC Connection (DCA) during construction of the AC island grid.
  13. 13. Method according to any of the preceding claims, wherein after construction of the AC island grid the at least one DC connection unit (16) of the electrical power supply unit (10) is connected in parallel for supplying electrical energy from the AC grid (12) to the DC Connection (DCA).
  14. 14. An electrical power supply unit (10) having a first power converter (22), a second power converter (24) and a rectifying unit (26) and being arranged for supplying electrical energy from an AC power grid (12) to a DC Connection (DCA), wherein at least one DC connection unit (14, 15, 16) is connectable to the DC Connection (DCA) of the electrical power supply unit (10) and the AC power grid (12) is connectable to an AC Connection (ACA) of the electrical power supply unit (10), wherein the power supply unit (10) is configured to: -pre-charging a first DC intermediate circuit of the first power converter (22) and a second DC intermediate circuit of the second power converter (24) from the AC power grid (12) via an AC pre-charging circuit (18), -Building an AC island grid by means of the second power converter (24), wherein during building of the AC island grid, electrical energy can be supplied from the AC island grid to the DC Connection (DCA) via the rectifying unit (26).
  15. 15. The electrical power supply unit according to claim 14, wherein the first power converter (22) is connected with the AC Connection (ACA) on the AC side and separated from the DC Connection (DCA) on the DC side during pre-charging of the first and second DC intermediate circuits.
  16. 16. The electrical power supply unit according to claim 14 or 15, wherein the second power converter (24) is separated from the AC Connection (ACA) on the AC side and connected to the DC side of the first power converter (22) on the DC side during pre-charging of the first and second DC intermediate circuits, wherein the DC sides of the first and second power converters (22, 24) are separated from the DC Connection (DCA) during pre-charging of the first and second DC intermediate circuits.
  17. 17. The electrical power supply unit according to any of claims 14 to 16, wherein the first power converter (22) and/or the second power converter (24) are connected with the AC Connection (ACA) on the AC side and with the DC Connection (DCA) on the DC side for supplying electrical energy from the AC electrical grid (12) to the DC Connection (DCA).
  18. 18. The electrical power supply unit according to any one of claims 14 to 17, wherein the rectifying unit (26) comprises a passive rectifier and/or a switched mode AC/DC converter.
  19. 19. The electrical power supply unit according to any of claims 14 to 18, wherein the at least one DC connection unit (14) is designed as an electrolysis cell that can be pre-charged via the DC Connection (DCA) during construction of the AC island grid.
  20. 20. The electrical power supply unit according to any one of claims 14 to 19, wherein electrical energy can be fed from the DC connection via the electrical power supply unit into the AC grid (12) connectable to the AC connection.

Description

Method for starting an electrolytic power supply device with parallel converters and a simplified pre-charging unit Technical Field The application relates to a method for starting an electrical power supply unit, an electrical power supply unit and an electrolytic power supply device. Background A method for starting up an electrolysis plant is described in WO2023/274776A 1. The electrolysis device comprises an electrolysis cell and a power supply unit operating as a rectifier. Wherein the power supply unit has an AC connection to an AC grid, a DC connection to an electrolyzer, and an AC/DC converter arranged between the AC connection and the DC connection. By operating the electrolytic cell in reverse mode, the output capacitor connected to the DC converter connection of the AC/DC converter is charged as a DC voltage source. This type of charging of the DC side of the AC/DC converter requires the consumption of hydrogen, which in practice should be generated in the electrolyzer. This type of charging on the DC side is therefore disadvantageous. There is a need to find an improved and resource-saving alternative to this approach. Alternatively, a pre-charging unit is used in the power supply unit of the electrolysis device, which is dedicated to pre-charging the electrolysis cell. Here, for example, an alkaline electrolysis cell, i.e. an electrolysis cell for Alkaline Electrolysis (AEL), is precharged to its no-load voltage of 700 to 800V, wherein such an electrolysis cell has a capacitance characteristic of 2F to 5F. In this case, it is common practice to increase the voltage for the cell pre-charging step by means of a pre-charging unit, so that the pre-charging voltage continues to rise to the no-load voltage of the cell. Furthermore, from an economical point of view, the electrolyzer should be operated as long as possible so that the system discharge only happens occasionally. Since the need for pre-charging is rare, the pre-charging unit is also designed to be smaller, i.e. to have less power, to save the cost of the pre-charging unit. The pre-charge duration of the electrolyzer is longer due to the lower power. In the prior art, there is therefore a pre-charging unit for an electrolytic cell, which is dedicated to pre-charging of the electrolytic cell, is rarely used for economic reasons and has a lower power. There is also a need to find a cost-effective, time-efficient alternative. SUMMARY The above problems are solved by the subject matter of the present invention. The electrical power supply unit according to the invention has a first power converter, a second power converter and a rectifying unit. The power supply unit is arranged for supplying power from an AC power grid (AC english ALTERNATING CURRENT: alternating current/alternating voltage) to DC connections (DC english direct current/direct voltage), wherein at least one DC connection unit is connectable to a DC connection of the power supply unit and an AC power grid is connectable to an AC connection of the power supply unit. For example, the DC link unit may be at least one DC source, at least one DC load and/or at least one further unit. Method for starting an electrical power supply unit, wherein at least one DC connection unit is connected to a DC connection of the power supply unit and an AC grid is connected to an AC connection of the power supply unit, the method comprising the steps of: The first DC intermediate circuit of the first power converter and the second DC intermediate circuit of the second power converter are pre-charged from the AC power grid via an AC pre-charging circuit, An AC island grid is built by the second power converter, wherein during the building of the AC island grid, electrical energy is supplied from the AC island grid to the DC link via the rectifying unit. The electrical power supply unit is configured to: The first DC intermediate circuit of the first power converter and the second DC intermediate circuit of the second power converter are pre-charged from the AC power grid via an AC pre-charging circuit, An AC island grid is built by the second power converter, wherein during the building of the AC island grid, electrical energy can be supplied from the AC island grid to the DC link via the rectifying unit. For example, the first power converter and the second power converter may be switching type inverters, which may also operate as rectifiers. The power converter is particularly designed for transmitting large powers, for example in the MW-class range. The pre-charging of the first and second DC intermediate circuits is used for controlled charging of the intermediate circuits to avoid excessive inrush currents. This contributes to safety and extends the service life of the assembly. The AC pre-charge circuit is, for example, designed to limit the current when charging the first DC intermediate circuit and the second DC intermediate circuit. To this end, for example, the AC precharge circuit may hav