Motor control apparatus equipped with delta-sigma modulation AD converter

摘要

A motor control apparatus includes a power conversion unit which supplies drive power to a motor, a current detection unit which detects the value of a current flowing from the power conversion unit to the motor, a delta-sigma modulation AD converter which converts the current value into digital data by using a modulation clock as a system clock, and which starts to count the number of clock pulses of the modulation clock upon reception of a reference signal and, when the number of clock pulses counted reaches a predetermined count value, outputs the digital data obtained during a prescribed time interval which contains the reception time of the reference signal, and a command generating unit which generates, using the digital data supplied from the delta-sigma modulation AD converter, a drive command for commanding the power conversion unit to output commanded drive power.

主权项

1. A motor control apparatus comprising:
a power conversion unit which supplies drive power to a motor; a current detection unit which detects the value of a current flowing from said power conversion unit to said motor; a delta-sigma modulation AD converter which converts said current value detected by said current detection unit into digital data by using a modulation clock as a system clock, wherein said delta-sigma modulation AD converter starts to count the number of clock pulses of said modulation clock upon reception of a reference signal and, when the number of clock pulses counted reaches a predetermined count value, outputs said digital data obtained during a prescribed time interval which contains the reception time of said reference signal; a command generating unit which generates, using said digital data supplied from said delta-sigma modulation AD converter, a drive command for commanding said power conversion unit to output commanded drive power; and a reference signal generating unit which generates and outputs a signal that defines timing for said command generating unit to acquire a current value necessary to create said desired drive command from said current value detected by said current detection unit as said reference signal, wherein said predetermined count value is set equal to one half of the number of modulation clock pulses that corresponds to said prescribed time interval.