CURRENT SENSING STRUCTURE OF THREE-PHASE MOTOR, CURRENT SENSING METHOD, MOTOR CONTROL SYSTEM AND MOTOR CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a current sensing structure of a three-phase motor capable of fetching a current value with low noise without deteriorating fetching accuracy or a response when fetching a motor current value during PWM control of the three-phase motor.SOLUTION: A current sensing structure 10 which performs current sensing in the three-phase motor includes: a gate width decision section 2 for deciding whether a PWM gate width in phases (U, V and W) is suitable for Q-axis current calculation; a Q-axis current calculation section 8 for calculating a Q-axis current on the basis of the decision made by the gate width decision section 2; and an unsuitable phase calculation section 5 by which, if there is a phase decided unsuitable in the gate width decision section 2, a calculation value is calculated upon receiving the decision. The "unsuitable case for calculation" is a case where a turn-on width of a PWM gate is wide at such a degree that current sensing cannot be performed or noise comes in switching during the PWM control.SELECTED DRAWING: Figure 1