Patent ID: 8519655
Filing Date: 2013-08-27
Classification: B60L,H02M,H02P,Y02T

Abstract:
1. A method for controlling an electric motor via a controller and a rectifier comprising a positive solid state switch and a negative solid state switch for each of three phases of input voltage, the rectifier converting three input phases of alternating current voltage to direct current voltage applied to a direct current bus, the method comprising, over a plurality of cycles of input voltage: (a) detecting the voltage of the direct current bus, and the voltage of each phase of input voltage; (b) determining motor braking activity; (c) identifying the phase of input voltage having the highest absolute voltage; (d) cycling the positive and negative solid state switches of the identified phase during motor braking activity so that voltage generated by the motor braking activity is directed to the source of the three input phases of alternating current voltage; and (e) placing a solid state switch for the two other phases in a conducting state based upon which other phase exhibits the greater voltage difference from the identified phase.