Pulsed electric machine control

A wound field synchronous electric machine (WFSM) comprising:

• a power converter;
• and
• a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the wound field synchronous electric machine system during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the wound field synchronous electric machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the wound field synchronous electric machine is at least 10 Hz.

A method of operating an electrically excited synchronous machine (EESM), the method comprising directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the electrically excited synchronous machine is at least 10 Hz.

A method of operating an electrically excited synchronous machine (EESM), the method comprising:

• directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output;
• and
• varying a pulsing frequency of the electrically excited synchronous electric machine based at least in part on noise or vibration considerations.

A method of operating an electrically excited synchronous machine (EESM), the method comprising:

• directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output;
• and
• wherein a sigma delta conversion is utilized to determine at least one of a timing of the outputted pulses, a duration of the outputted pulses, a frequency of the outputted pulses and a pulse cycle duration of the outputted pulses, the pulse cycle duration being a period between beginnings of sequential pulses.

An externally excited synchronous machine comprising:

• a power converter;
• and
• a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the externally excited synchronous machine system during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the externally excited synchonous machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the externally excited synchronous machine is at least 10 Hz.