SENSORLESS SPEED CONTROL APPARATUS AND METHOD FOR BRUSHLESS DC MOTOR

摘要

PURPOSE: A sensorless speed control apparatus and a method for brushless DC motor are provided to achieve an improved estimation performance while eliminating use of complicated speed sensor. CONSTITUTION: An apparatus comprises a speed command output unit, a speed controller, a current controller, a power rectifier, a current detector, and a binary observation unit. The binary observation unit includes an adder(61) for obtaining estimation error between the actual current flowing at the brushless DC motor and the estimated current obtained from an equation of state; an auxiliary loop adjuster(62) for setting the limit range of tolerance of the estimation error obtained by the adder, and setting the gain of a main loop adjuster(63) in such a manner that the estimation error stays within the limit range when the estimation error falls into the limit range; the main loop adjuster for taking as an input, the output from the auxiliary main loop adjuster and the estimation error of the adder, and outputting a series of switching functions; and a gain adjuster(64) for allowing the error trajectory came into the limit range to be stably converged to the origin by adjusting gains of switching functions output from the main loop adjuster.