Patent ID: 6329781
Filing Date: 2001-12-11
Classification: B60L,Y02T

Abstract:
A control apparatus of a permanent-magnet synchronous electric motor driven by power supplied by a battery through an inverter circuit, said control apparatus comprising:a current-command generation means for outputting a d-axis current command and a q-axis current command to said permanent-magnet synchronous electric motor;a current detection means for detecting a d-axis current and a q-axis current of said synchronous electric motor from phases and 3-phase alternating-current values of said synchronous-electric motor;a compensation computation means for computing a d-axis voltage compensation value and a q-axis voltage compensation value on the basis of said d-axis current command, said q-axis current command, a detected value of said d-axis current and a detected value of said q-axis current;a voltage-command generation means for generating a 3-phase alternating-current voltage command from said d-axis voltage compensation value, said q-axis voltage compensation value and phases as well as a rotational speed of said synchronous electric motor; anda PWM (Pulse Width Modulation) control means for generating a PWM signal for driving a power device of said inverter circuit from a value of said 3-phase alternating-current voltage command,wherein, in performing field weakening control of said motor, a start rotational speed for execution of said field weakening control is corrected in accordance with a detected value of a voltage of said battery so that, when said voltage of said battery is high, said start rotational speed is increased while, when said voltage of said battery is low, said start rotational speed is decreased.