Fault protection for voltage source converters
First Claim
1. An apparatus for a voltage source converter comprising:
- a chain-link circuit in series with a director switch; and
a fault controller;
wherein the chain-link circuit comprises a plurality of cells, each cell comprising an energy storage element and a plurality of cell switching elements connected with antiparallel diodes, the cell switching elements being configured such that the energy storage element can be selectively connected in series between terminals of the cell or bypassed;
wherein each cell switching element has an associated cell switching element controller;
wherein the director switch comprises a plurality of director switch units, each director switch unit comprising a director switching element and a director switch unit controller;
wherein each cell switching element controller is configured to monitor for a fault current and, in the event a fault current is detected, to turn-off its associated cell switching element and report a fault event to the fault controller;
wherein each director switch unit controller is configured to monitor for a fault current and, in the event a fault current is detected, to report a fault event to the fault controller and to keep its associated director switching element turned-on; and
wherein the fault controller is configured to monitor for any reports of fault events to determine whether a fault is occurring and, in the event that a fault is occurring, to order all of the cell switching elements of at least some of the plurality of cells to turn-off.
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Accused Products
Abstract
Fault protection of a voltage source converter is provided. An apparatus has a chain-link circuit in series with a director switch. The chain-link circuit includes cells including an energy storage element and cell switching elements connected with anti-parallel diodes. Each cell switching element has a cell switching element controller. The director switch includes director switch units, each having a director switching element and a director switch unit controller. Each cell switching element controller monitors for a fault current and turns-off its associated cell switching element and reports a fault event to a fault controller. Each director switch unit controller monitors for a fault current and reports a fault event to the fault controller but the director switch unit control keeps its associated director switching element turned-on. The fault controller monitors for reports of fault events to order the cell switching elements of at least some of the cells to turn-off.
13 Citations
15 Claims
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1. An apparatus for a voltage source converter comprising:
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a chain-link circuit in series with a director switch; and a fault controller; wherein the chain-link circuit comprises a plurality of cells, each cell comprising an energy storage element and a plurality of cell switching elements connected with antiparallel diodes, the cell switching elements being configured such that the energy storage element can be selectively connected in series between terminals of the cell or bypassed; wherein each cell switching element has an associated cell switching element controller; wherein the director switch comprises a plurality of director switch units, each director switch unit comprising a director switching element and a director switch unit controller; wherein each cell switching element controller is configured to monitor for a fault current and, in the event a fault current is detected, to turn-off its associated cell switching element and report a fault event to the fault controller; wherein each director switch unit controller is configured to monitor for a fault current and, in the event a fault current is detected, to report a fault event to the fault controller and to keep its associated director switching element turned-on; and wherein the fault controller is configured to monitor for any reports of fault events to determine whether a fault is occurring and, in the event that a fault is occurring, to order all of the cell switching elements of at least some of the plurality of cells to turn-off. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of fault protection for a voltage source converter comprising a chain-link circuit in series with a director switch;
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wherein the chain-link circuit comprises a plurality of cells, each cell comprising an energy storage element and a plurality of cell switching elements connected with antiparallel diodes, the cell switching elements being configured such that the energy storage element can be selectively connected in series between terminals of the cell or bypassed; and wherein the director switch comprises a plurality of director switch units, each director switch unit comprising a director switching element; the method comprising; monitoring at each cell switching element for a fault current and, in the event a fault current is detected at a cell switching element, turning-off that cell switching element and reporting a fault event to a fault controller; monitoring at each director switching element for a fault current and, in the event a fault current is detected, reporting a fault event to the fault controller and keeping that director switching element turned-on; and monitoring at the fault controller for any reports of fault events to determine whether a fault is occurring and, in the event that a fault is occurring, ordering all of the cell switching elements of at least some of the plurality of cells to turn-off. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification