a motor drive system is disclosed that includes a power input configured to receive alternating current power and a rectifier having a switching frequency selected to convert the ac power to direct current power . the motor drive unit also includes an input filter circuit connected between the power input and the rectifier and configured to suppress frequency harmonics across a range of harmonics . additionally , the motor drive unit includes a block filter circuit connected between the power input and the rectifier and configured to substantially block frequency harmonics associated with the switching frequency of the rectifier . furthermore , the motor drive unit includes an inverter configured to receive the dc power from the rectifier and convert the dc power to a series of pulses configured to drive a motor .