DRIVE SYSTEM OF SYNCHRONIZED ELECTRIC MOTOR

摘要

A synchronous electric motor drive system capable of driving at speeds near zero is provided. An energization mode determination unit 9 switches six energization modes successively based on a terminal potential value detected of the de-energized phase of a three-phase synchronous electric motor 4 or on a stator winding wire connection point potential value (neutral point potential) detected of the three-phase synchronous transmission unit. A voltage command correction unit 8 corrects by a correction amount ”V an applied voltage command destined for the synchronous electric motor so as to supply the synchronous electric motor with a repeated waveform of a positive pulse voltage, a negative pulse voltage, and a zero voltage as a line voltage waveform of the energized phases in each of the six energization modes, the positive pulse voltage being polarized to cause the synchronous electric motor to generate a forward rotation torque, the negative pulse voltage causing the synchronous electric motor to generate a reverse rotation torque. The line voltage of the energized phases is applied to the synchronous electric motor.