CURRENT DETECTION METHOD, INVERTER DEVICE AND CONVERTER DEVICE UTILIZING CURRENT DETECTION METHOD, MOTOR DRIVE EQUIPPED WITH SUCH DEVICE, AND REFRIGERATION AND AIR-CONDITIONING EQUIPMENT

摘要

PPROBLEM TO BE SOLVED: To provide a current detection method which is operated stably even in an overmodulation region, an inverter device, and a converter device utilizing that method, a motor drive of a low cost, and refrigeration and air-conditioning equipment. PSOLUTION: In the motor drive equipped with: an AC motor; an inverter which drives the AC motor; a current detection means for detecting the bus current on the DC side of the inverter or each arm current; and a control means for controlling the AC motor by using the current detection values thus detected, an AC motor current reference value is calculated from the current detection value in the past which is obtained from the current detection means or the current command value of the control means, and when the current detection means detects only the current of one phase of the AC motor, an error between the current detection value of one phase and the current reference value is calculated, and then the undetectable phase current of the AC motor is estimated using the error. PCOPYRIGHT: (C)2011,JPO&INPIT