Protection circuits and methods for electrical machines
AssigneeGE Energy Power Conversion Technology Limited
InventorEric Anthony Lewis
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Abstract
An assembly includes an electrical machine connected to a power converter by a three-phase circuit having three conductors, e.g. cables Each conductor is associated with a switching device such as a contactor or the like that connects the conductor to a common conductor or terminal. In the event of a fault current being developed in the circuit or the power converter the switching devices are operated to close the fault current and connect together the conductors of the three-phase circuit to provide a full three-phase short circuit.
Claims14
An electrical machine having an at least one multiple-phase stator winding connected to a power converter in a multiple-phase circuit by a group of cables each carrying a respective phase of the multiple-phase circuit, the machine comprising:
- an electrical protection circuit including a switching device including a group of contacts connected between the electrical machine and the power converter via a first connection;
- a controller communicatively connected to the power converter and to the electrical protection circuit, wherein the controller is configured to sense fault current and configured to activate the electrical protection circuit;
- and
- a common conductor connected to the group of contacts of the electrical assembly via a second connection opposite the first connection,
- wherein each cable of the group of cables is connected in parallel to the common conductor by a separate contact of the group of contacts, and when a fault occurs, the group of contacts is closed to connect each cable of the group of cables to the common conductor and to short-circuit a total of the respective phases of the multiple-phase circuit.
An electrical machine having an electrical protection circuit, the electrical machine comprising:
- a power converter electrically connected to the electrical machine in a multiple-phase circuit by a group of cables, wherein the electrical machine is a multiple phase motor having an at least one multiple-phase stator winding;
- the electrical protection circuit including a switching device including a group of contacts connected between the electrical machine and the power converter via a first connection;
- a controller communicatively connected to the power converter and to the electrical protection circuit, wherein the controller is configured to sense fault current and configured to activate the electrical protection circuit;
- a common conductor connected to the group of contacts of the electrical protection circuit by a second connection opposite the first connection, wherein each cable of the group of cables is connected in parallel to the common conductor by a separate contact of the group of contacts, and when a fault occurs the group of contacts is closed to connect each cable of the group of cables to the common conductor and to short-circuit a total of the respective phases of the multiple-phase circuit.
A method of protecting an electrical machine having an at least one 3-phase stator winding electrically connected to a power converter by a group of three separate cables, each cable carrying a respective phase of the at least one 3-phase stator winding, wherein the electrical machine further having a common conductor connected in parallel to each cable of the group of three separate cables by an associated contact of an electrical protection circuit, wherein the electrical protection circuit including a switching device including a group of contacts between the electrical machine and the power converter and the electrical machine further having a controller communicatively connected between the power converter and the electrical protection circuit the method comprising:
- sensing, by the controller, a fault current;
- activating the electrical protection circuit to close the associated contact connected to each cable of the group of three separate cables based on the fault current sensed;
- and
- short-circuiting a total of the respective phases.
Dependencies are inferred from the claim text.