System and method for preventing permanent magnet demagnetization in electrical machines
First Claim
1. A motor drive for driving an electrical machine having one or more permanent magnets therein, the motor drive comprising:
- an inverter having a plurality of switches therein that are selectively operated to control current flow and terminal voltages in the electrical machine; and
a controller operatively connected to the inverter and configured to control switching of the plurality of switches to control the current flow and terminal voltages in the electrical machine, the controller being programmed to;
analyze at least one of voltages and currents provided to the electrical machine on one or more phases to identify a fault condition in the electrical machine; and
control switching of the plurality of switches in the inverter to modify current flow and terminal voltages in the electrical machine based on the identified fault condition, so as to prevent demagnetization of the one or more permanent magnets in the electrical machine.
1 Assignment
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Accused Products
Abstract
A motor drive for driving a permanent magnet electrical machine includes an inverter having switches that are selectively operated to control current flow and terminal voltages in the electrical machine and a controller operatively connected to the inverter to control switching of the switches to control the current flow and terminal voltages in the electrical machine. The controller receives inputs regarding at least one of currents and voltages provided to the electrical machine on one or more phases, analyzes the voltages and currents to identify a fault in the electrical machine, and controls switching of the plurality of switches in the inverter to modify current flow and terminal voltages in the electrical machine based on the identified fault, with the modified current flow and terminal voltages in the electrical machine preventing demagnetization of the permanent magnets in the electrical machine.
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Citations
25 Claims
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1. A motor drive for driving an electrical machine having one or more permanent magnets therein, the motor drive comprising:
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an inverter having a plurality of switches therein that are selectively operated to control current flow and terminal voltages in the electrical machine; and a controller operatively connected to the inverter and configured to control switching of the plurality of switches to control the current flow and terminal voltages in the electrical machine, the controller being programmed to; analyze at least one of voltages and currents provided to the electrical machine on one or more phases to identify a fault condition in the electrical machine; and control switching of the plurality of switches in the inverter to modify current flow and terminal voltages in the electrical machine based on the identified fault condition, so as to prevent demagnetization of the one or more permanent magnets in the electrical machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for implementing a post-fault protection technique for preventing demagnetization of permanent magnets in an electrical machine, the method comprising:
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monitoring, via a controller, at least one of voltages and currents supplied to the electrical machine; analyzing, via the controller, the at least one of the voltages and currents supplied to the electrical machine to detect a fault condition in the electrical machine; determining, via the controller, a fault type of the detected fault condition based on the analyzed at least one of the voltages and currents; and modifying, via the controller, the voltages and currents supplied to the electrical machine on at least one phase based on the determined fault type; wherein modifying the voltages and currents supplied to the electrical machine on the at least one phase constrains a fault current in the electrical machine, so as to control a negative d-axis magnetic flux in the electrical machine and thereby prevent demagnetization of the permanent magnets. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A controller configured to control operation of an inverter so as to control currents and voltages output to a permanent magnet electrical machine connected thereto, the controller having a processor programmed to:
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receive inputs regarding at least one of currents and voltages provided to the permanent magnet electrical machine on one or more phases; analyze the at least one of the voltages and currents to identify a fault in the permanent magnet electrical machine; and upon identification of a fault, control switching of a plurality of switches in the inverter to modify the currents and voltages provided to the permanent magnet electrical machine based on a type of the identified fault; wherein the modified currents and voltages provided to the permanent magnet electrical machine maintain a d-axis magnetic flux in the permanent magnet electrical machine at a level that prevents demagnetization of one or more permanent magnets therein. - View Dependent Claims (22, 23, 24, 25)
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Specification