Control apparatus of a synchronous motor

Abstract

A control apparatus of a synchronous motor with a load commutated inverter includes a positive/negative judgment unit for discriminating positive/negative of the motor voltage of each phase of the three-phase AC input of the synchronous motor, an estimated phase setting unit for calculating and setting the estimated phase of the motor voltage based on the discrimination result by the positive/negative discrimination unit, and a speed estimation unit for estimating the speed of the synchronous motor by integrating the change of the estimated phase by a predetermined number of times and dividing the integrated result by the product of the predetermined number and the operation cycle. When driving the synchronous motor with the load commutated inverter, in a condition the synchronous motor slips at high speed, restart is made easier.

Dependencies are inferred from the claim text.