MOTOR CONTROL SYSTEM, OPEN-PHASE DETECTION DEVICE, AND OPEN-PHASE DETECTION METHOD

摘要

PPROBLEM TO BE SOLVED: To provide a motor control system that can surely detects an open phase by a simple constitution. PSOLUTION: A conveyance truck 1 is provided with a three-phase AC motor 5F; a power supply portion 25 which supplies three-phase AC power to the motor 5F; current detection portions 27u, 27v, and 27w that detect currents of phases supplied from the power supply portion 25 to the motor 5F; an encoder 13 which detects revolutions of the motor 5F; a dq conversion portion 29 which performs the dq-conversion of the detected currents Iu, Iv and Iw of phases from the detected phase of the encoder 13 and calculates a d-axis current Id and a q-axis current Iq; and an open-phase detection portion 9 which outputs an open-phase detection signal Sf when an absolute value of the d-axis current Id calculated by the dq conversion portion 29 exceeds a predetermined threshold Th and the ratio of the absolute value of the d-axis current Id to that of the q-axis current Iq is held within a predetermined range. PCOPYRIGHT: (C)2008,JPO&INPIT