Patent ID: 7952310

Claim:
A controller of a multi-phase electric motor comprising: a drive section, including a pair of upper arm switching element and a lower arm switching element, for driving the multi-phase electric motor; a single current detection section for detecting a current value of the multi-phase electric motor; a pulse width modulation signal generation section for generating a pulse width modulation signal of each phase based on the current value detected by the current detection section and a saw-tooth signal having a predetermined frequency; a current detectability determination section for determining whether or not the current value is detectable in the current detection section based on the pulse width modulation signal of each phase generated by the pulse width modulation signal generation section; a switching number determination section for determining whether or not conducting number of the upper arm switching element is an even number or an odd number based on the determination that the current is not detectable by the current detectability determination section; a phase movement section for moving a phase of the pulse width modulation signal of a predetermined phase generated by the pulse width modulation signal generation section based on the determination result of the switching number determination section and outputting to the drive section; and each phase current calculation section for calculating a current value of each phase based on the current value detected by the current detection section and the pulse width modulation signal of each phase generated by the pulse width modulation signal generation section.