Patent ID: 7026771

Claim:
A motor control apparatus which controls operation of an A.C. driven motor, comprising: a switching element which is activated by a trigger signal; a zero-cross detection section configured to detect a zero-crossing point of A.C. power voltage applied to the motor; a current detection section configured to detect a load current flowing through the motor; and a control section associated with the zero-cross detection section and the current detection section, configured to supply the trigger signal to the switching element, the control section including, a first means for obtaining a load current instant value by sampling the load current detected by the current detection section at a prescribed sampling period, a functional value output means for outputting a sine-functional value in response to the prescribed sampling period of the load current, a total value calculation means for obtaining a compensation value for each load current instant value based on the load current instant value from the first means and the sine-functional value from the functional value output means to calculate a load current compensation total value by adding the compensation values over the number of times of sampling, and a timing determination means for obtaining a difference by comparing the load current compensation total value with a load current reference value to determine an output timing of the trigger signal to the switching element in response to the difference so that power consumption of the motor falls within a predetermined range.