PORTABLE APPLIANCE MOTOR CONTROL WITH SPEED-BASED CURRENT LIMITATION

摘要

A method for controlling a portable appliance (10) includes: measuring an input current supplied to a motor (18) of the portable appliance (10) and measuring a rotational speed of a shaft (60) of the motor (18); determining a current limit based on the rotational speed of the shaft (60) using a substantially continuous function which relates a domain of rotational speeds to a range or current limits; and when the input current exceeds the current limit, reducing the rotational speed of the shaft (60) incrementally along the substantially continuous function until the input current is approximately equal to the current limit.