Synchronous electric motor drive system

摘要

A synchronous electric motor drive system capable of driving at speeds near zero is provided. An energization mode determination unit switches six energization modes successively based on a terminal potential detected of the de-energized phase of a three-phase synchronous electric motor or on a stator winding wire connection point potential (neutral point potential) detected of the three-phase synchronous transmission unit. A voltage command correction unit corrects by a correction amount ΔV an applied voltage command destined for the synchronous electric motor to supply the synchronous electric motor with a repeated waveform of a positive pulse, negative pulse, and 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.

主权项

1. A synchronous electric motor drive system comprising:
a three-phase synchronous electric motor; an inverter supplying alternate-current power to the three-phase synchronous electric motor and including a plurality of switching elements, and a controller controlling energization of the inverter through pulse width modulation in one of six energization modes by selecting two phases to be energized out of three phases of winding wires of the three-phase synchronous electric motor; wherein the controller has an energization mode determination unit for switching the energization modes successively based on a terminal potential value detected of the de-energized phase of the three-phase synchronous electric motor or on a stator winding wire connection point potential value (neutral point potential) detected of the three-phase synchronous transmission unit; wherein the controller has a voltage command correction unit for correcting 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, and wherein the line voltage of the energized phases is applied to the synchronous electric motor.