Controller for a permanent magnet machine
A controller for a permanent magnet machine, the controller configured to: monitor a characteristic value of power transfer to the permanent magnet machine; compare the monitored characteristic value to a characteristic threshold; and indicate a short circuit error in response to the monitored characteristic value meeting the characteristic threshold.
1 . An apparatus comprising:
a controller for a permanent magnet machine, the controller configured to:
monitor a characteristic value of power transfer to the permanent magnet machine;
compare the monitored characteristic value to a characteristic threshold;
indicate a short circuit error in response to the monitored characteristic value meeting the characteristic threshold; and
bring the permanent magnet machine to rest in response to the short circuit error being indicated.
2 . The apparatus according to claim 1 , wherein the controller is configured to physically disconnect the permanent magnet machine from a power source after bringing the permanent magnet machine to rest.
3 . The apparatus according to claim 1 , wherein the characteristic value comprises a current.
4 . The apparatus according to claim 3 , wherein the current comprises a total current in a DC power link.
5 . The apparatus according to claim 3 , wherein the current comprises a Q-axis current.
6 . The apparatus according to claim 3 , wherein the characteristic threshold relates to a characteristic current variance, and wherein the controller is configured to indicate the short circuit error when a variance of the current exceeds the characteristic current variance.
7 . The apparatus according to claim 1 , wherein the characteristic value relates to a frequency of the power transfer.
8 . The apparatus according to claim 7 , wherein the controller is configured to indicate the short circuit error in response to the frequency being lower than the characteristic threshold.
9 . The apparatus according to claim 1 , wherein the controller is configured to control the permanent magnet machine to operate as a motor.
10 . The apparatus according to claim 9 , wherein the characteristic value comprises a motor torque.
11 . The apparatus according to claim 1 , wherein the controller is configured to control the permanent magnet machine to operate as a generator.
12 . The apparatus according to claim 1 , wherein the permanent magnet machine is a surface permanent magnet machine.
13 . An aircraft power system comprising:
a permanent magnet machine; and
a controller configured to:
monitor a characteristic value of power transfer to the permanent magnet machine;
compare the monitored characteristic value to a characteristic threshold;
indicate a short circuit error in response to the monitored characteristic value meeting the characteristic threshold; and
bring the permanent magnet machine to rest in response to the short circuit error being indicated.
14 . The aircraft power system according to claim 13 , further comprising a DC power link and an inverter/rectifier, the inverter/rectifier configured to convert between DC power in the DC power link and AC power in the permanent magnet machine.
15 . An aircraft comprising the aircraft power system of claim 13 .
16 . A method of detecting a shorted turn fault in a permanent magnet machine, the method comprising:
monitoring a characteristic value of power transfer to the permanent magnet machine;
comparing the monitored characteristic value to a characteristic threshold;
indicating a short circuit error in response to the monitored characteristic value meeting the characteristic threshold; and
bringing the permanent magnet machine to rest in response to the short circuit error being indicated.
17 . The method according to claim 16 , wherein the characteristic value relates to a frequency of the power transfer.
18 . The method according to claim 16 , wherein:
the characteristic value comprises a current;
the characteristic threshold relates to a characteristic current variance; and
the short circuit error is indicated when a variance of the current exceeds the characteristic current variance.
19 . The aircraft power system according to claim 13 , wherein the characteristic value relates to a frequency of the power transfer.
20 . The aircraft power system according to claim 13 , wherein:
the characteristic value comprises a current;
the characteristic threshold relates to a characteristic current variance; and
the controller is configured to indicate the short circuit error when a variance of the current exceeds the characteristic current variance.