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US-12627234-B2 - Power conversion system

US12627234B2US 12627234 B2US12627234 B2US 12627234B2US-12627234-B2

Abstract

A power conversion system includes a high voltage (HV) switchgear; a solid-state transformer; and a low voltage (LV) switchgear. The HV switchgear connects to and disconnects from a HV network. The HV switchgear connects to an input of the solid-state transformer, which comprises first and second modules. The first module converts an HV alternating current (AC) signal into a HV DC signal, and the first module converts an HV DC signal into an HV AC signal. The second module converts an HV DC signal into at least one LV DC signal, and the second module converts at least one LV DC signal into an HV DC signal. The LV switchgear connects to an output of the solid-state transformer. The LV switchgear connects to a plurality of applications or devices and disconnects from the plurality of applications or devices.

Inventors

  • Radek Javora
  • Carlos David Martinez Nieto
  • Andreas BRANDT

Assignees

  • ABB SCHWEIZ AG

Dates

Publication Date
20260512
Application Date
20240724
Priority Date
20220124

Claims (15)

  1. 1 . A power conversion system, comprising: a high voltage (HV) switchgear; a solid-state transformer; and a low voltage (LV) switchgear; wherein the HV switchgear is configured to connect to an HV network and disconnect from the HV network; wherein the HV switchgear is configured to connect to an input of the solid-state transformer; wherein the solid-state transformer comprises a first module and a second module connected to the first module; wherein the first module is configured to convert a HV alternating current (AC) signal from the high voltage network into a HV direct current (DC) signal, and wherein the first module is configured to convert the HV DC signal from the second module into a HV AC signal to be provided to the high voltage network; wherein the second module is configured to connect to an output of the first module, wherein the second module is configured to convert the HV DC signal from the first module into at least one LV DC signal, and wherein the second module is configured to convert at least one LV DC signal into an HV DC signal to be provided to the first module; wherein the second module comprises at least one submodule configured to convert the HV DC signal from the first module into the LV DC signal, the submodule comprising a DC to AC converter, a medium frequency transformer, and an AC to DC converter; wherein the LV switchgear is configured to connect to an output of the solid-state transformer; wherein the LV switchgear is configured to connect to a plurality of applications or devices and to disconnect from the plurality of applications or devices; and wherein the system is configured to transfer power from the HV network to the plurality of applications or devices; and wherein the system is configured to transfer power from the plurality of applications or devices to the HV network.
  2. 2 . The power conversion system according to claim 1 , wherein the system is further configured to transfer power from the HV network to one or more of the plurality of applications or devices, wherein the HV switchgear is configured to connect to the HV network, wherein the first module is configured to convert a HC AC signal from the HV network into a HV DC signal, wherein the second module is configured to connect to an output of the first module and convert the HV DC signal from the first module into at least one LV DC signal, wherein the second module comprises at least one sub-module, wherein each sub-module is configured to convert the HV DC signal from the first module into a LV DC signal, and wherein the LV switchgear is configured to connect to the one or more of the plurality of applications or devices.
  3. 3 . The power conversion system according to claim 2 , wherein the LV switchgear comprises a plurality of switches, wherein each switch is configured to connect to an application or device, and wherein the LV switchgear is configured to connect the at least one LV DC signal from the second module to the one or more of the plurality of applications or devices.
  4. 4 . The power conversion system according to claim 2 , wherein the LV switchgear is configured to connect the LV DC signal from each sub-module to the plurality of applications or devices.
  5. 5 . The power conversion system according to claim 2 , wherein the second module is configured to utilize a number of sub-modules in series or parallel dependent upon a power demand to the plurality of applications or devices.
  6. 6 . The power conversion system according to claim 1 , wherein the system is configured to transfer power from one or more of the plurality of applications or devices to the HV network, wherein the LV switchgear is configured to connect to the one or more of the plurality of applications or devices, wherein the LV switchgear comprises a plurality of switches, wherein each switch is configured to connect to an application or device, and wherein the LV switchgear is configured to connect at least one LV DC signal from the one or more of the plurality of applications or devices to the second module, wherein the second module is configured to convert the at least one LV DC signal from the one or more of the plurality of applications or devices into an HV DC signal, wherein the second module comprises at least one sub-module, wherein each sub-module is configured to convert a LV DC signal into a HV DC signal, wherein the first module is configured to connect to the second module and convert the HV DC signal into an HV AC signal, and wherein the HV switchgear is configured to connect the HV AC signal from the first module to the HV network.
  7. 7 . The power conversion system according to claim 6 , wherein the LV switchgear is configured to connect to the plurality of applications or devices, and wherein the LV switchgear is configured to connect a plurality of LV DC signals from the plurality of applications or devices to the second module.
  8. 8 . The power conversion system according to claim 6 , wherein the second module is configured to utilize a number of sub-modules in series or parallel dependent upon a power demand from the plurality of applications or devices.
  9. 9 . The power conversion system according to claim 6 , wherein each sub-module comprises an AC to DC converter, a medium frequency transformer and a DC to AC converter, wherein the DC to AC converter is configured to convert the LV DC signal from an application or device into an LV AC signal, wherein the medium frequency transformer is configured to convert the LV AC signal from the DC to AC converter into an HV AC signal, and wherein the AC to DC converter is configured to convert the HV AC signal from the medium frequency transformer into the HV DC signal to be provided to the first module.
  10. 10 . The power conversion system according to claim 1 , wherein the system is configured to transfer power from the HV network to one or more of the plurality of applications or devices and at the same time transfer power from a different one or more of the plurality of applications or devices to the HV network.
  11. 11 . The power conversion system according to claim 1 , wherein the LV switchgear is configured to connect to two or more applications or devices of the plurality of applications or devices to connect the two or more applications or devices to each other.
  12. 12 . The power conversion system according to claim 1 , wherein the LV switchgear is configured to disconnect power from the solid-state transformer.
  13. 13 . The power conversion system according to claim 11 , wherein the LV switchgear is configured to connect the two or more applications or devices to each other.
  14. 14 . The power conversion system according to claim 1 , wherein the solid-state transformer is configured to utilize a number of second modules in parallel dependent upon a power demand to and/or from the plurality of applications or devices.
  15. 15 . The power conversion system according to claim 1 , wherein for providing LV AC auxiliary power one or more DC to AC converters are located between the second module and the LV switchgear or the one or more DC to AC converters are located on output connections of the LV switchgear.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The instant application claims priority to International Patent Application No. PCT/EP2023/050100, filed Jan. 4, 2023, and to European Patent Application No. 22152990.2, filed Jan. 24, 2022, each of which is incorporated herein in its entirety by reference. FIELD OF THE DISCLOSURE The present invention relates to a power conversion system. BACKGROUND OF THE INVENTION In a general aspect, power conversion requires there to be several independent devices involved. Power comes from a medium voltage (MV) or high voltage (HV) network to a power transformer, which converts the voltage to a low voltage (LV) level, which is still at a frequency of a power system that provided the power. This LV alternating current (AC) output is then converted to a LV direct current (DC) output and such a LV DC signal is then further used for LV applications. A conventional layout of HV or MV AC to LV DC power conversion is shown in FIG. 1. Such a low frequency (typically within 2-200 Hz) power transformer can also provide galvanic insulation between the LV DC network/application and the HV/MV grid for safety purposes. Nevertheless, this bulky power transformer occupies a large space within an overall conversion system, consumes a lot of raw materials, has significant weight, and creates power losses. Furthermore, power flow is enabled only in one direction, i.e. from the HV network to the LV DC application that is consuming generated power. Each LV DC application needs its own DC power supply supporting a particular voltage/current rating or it needs to be powered from the HV network, which results in many devices installed in the network. BRIEF SUMMARY OF THE INVENTION It would be advantageous to have an improved technique to more flexibly convert power. In a first aspect, there is provided a power conversion system, comprising: a high voltage (HV) switchgear, a solid-state transformer (SST), and a low voltage (LV) switchgear. The HV switchgear is configured to connect to a high voltage (HV) network and disconnect from the HV network. The HV switchgear is configured to connect to an input of the solid-state transformer. The solid-state transformer comprises a first module and a second module connected to the first module. The first module is configured to convert a high voltage alternating current (HV AC) signal into a high voltage direct current (HV DC) signal, and the first module is configured to convert a HV DC signal into a HV AC signal. The second module is configured to convert a HV DC signal into at least one low voltage direct current (LV DC) signal, and the second module is configured to convert at least one LV DC signal into a HV DC signal. The LV switchgear is configured to connect to an output of the solid-state transformer. The LV switchgear is configured to connect to a plurality of applications or devices and configured to disconnect from the plurality of applications or devices. The system is configured to transfer power from the HV network to the plurality of applications or devices. The system is configured to transfer power from the plurality of applications or devices to the HV network. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) FIG. 1 is a diagram of a conventional layout of HV or MV AC to LV DC power conversion in accordance with the state of the art. FIG. 2 is a schematic representation of a new power conversion system in accordance with the disclosure. FIG. 3 is a schematic representation of a solid-state transformer of a new power conversion system in accordance with the disclosure. FIG. 4 is a schematic representation of an architecture of a solid-state transformer of a new power conversion system in accordance with the disclosure. FIG. 5 is a schematic representation of an architecture of a solid-state transformer of a new power conversion system for AC applications in accordance with the disclosure. FIG. 6 is a schematic representation of a new power conversion system for AC and DC applications in accordance with the disclosure. FIG. 7a is a schematic representation of a new power conversion system with power flow from a HV (or MV) network towards applications or devices consuming power in accordance with the disclosure. FIG. 7b is a schematic representation of a new power conversion system with power flow from applications or devices where power is available to a HV (or MV) network in accordance with the disclosure. FIG. 7c is a schematic representation of a new power conversion system with power flow between applications or devices in accordance with the disclosure. FIG. 7d is a schematic representation of a new power conversion system with power flow from several possible sources in accordance with the disclosure. FIG. 7e is a schematic representation of a new power conversion system with mixed power flow from several possible sources in accordance with the disclosure. DETAILED DESCRIPTION OF THE INVENTION FIGS. 2-7 relate to a new power convers