PURPOSE: To enable highly accurate control on position, speed and torque, including those in proximity to 0°, by estimating magnetic flux position from inductance based on a phenomenon in which inductance varies depending on the positional relation between winding and motor magnetic flux.
CONSTITUTION: A.c. voltage is superposed on an output voltage command value of an inverter 1. The motor 2 current component that flows according to the result of the superposition is detected using a current component detector 7, and leakage inductance of the motor 2 winding is determined from the A.c. voltage and current. Then magnetic flux position (rotational angle) 1 is estimated from inductance using a phenomenon in which inductance varies depending on the positional relation between the motor 2 winding and the motor 2 magnetic flux. The phase of the inverter 1 output voltage and the exciting component and torque component (equivalent to secondary current) of the motor 2 current, are controlled according to the estimated magnetic flux angle 1. This makes possible highly accurate control on position, speed and torque, including those in proximity to zero speed.
IWAJI YOSHINAO
IKIMI TAKASHI
