Patent ID: 8169172

Claim:
A variable speed drive for an electric motor comprising: an inverter for receiving pulse width modulation controls, said inverter for communicating power signals to a poly-phase motor; a resolver for communicating signals from said poly-phase motor back to a motor control; the motor control including a speed control, a field-oriented control, and a pulse width modulation drive for driving said inverter, and said resolver being connected to said speed control and to said field-oriented control, and said resolver further communicating with a synchronous compensator, said synchronous compensator being configured to drive harmonic content of at least one target harmonic frequency in a selected signal towards zero over time; said synchronous compensator including a Fourier coefficient computation, which communicates signals into a Fourier component reconstruction, with said signals from said Fourier component reconstruction being communicated to a summation block along with an angular feedback signal from said resolver; and the output of said summation signal passing into a phase lock loop circuit, said phase lock loop circuit providing a filtered signal of an angular position of the poly-phase motor into the Fourier coefficient computation.