Apparatus for driving and controlling synchronous motor using permanent magnets as its field system

摘要

When a rotational speed (N) of a synchronous motor (14) using permanent magnets as its field system is equal to or higher than a base rotational speed (NB), a current condition computing section (16) computes a field weakening reference current (Id*) in accordance with a battery voltage (Vdc), reference torque (T*), and the rotational speed (N). An inverter (12) performs the field weakening control of the synchronous motor (14) in accordance with the field weakening reference current (Id*) sent from the current condition computing section (16) to prevent the deterioration of efficiency and the deficiency of output due to excessive or insufficient field weakening current (Id). The current condition computing section (16) determines an optimum reference current (Id*, Iq*) by using a converged battery voltage (VS) when the battery voltage (Vdc) is converged after initial control.