Patent ID: 6724166
Filing Date: 2004-04-20
Classification: G05B,H02P

Abstract:
An apparatus for reducing motor driving noise, comprising:a plurality of switching circuits each including at least a pair of switching elements connected in series between a power supply and a ground; a motor, one end of each of its phase windings is connected to a switching element serial connection point of each of said switching circuits; a noise reducing circuit for generating a current increasing signal and a current reducing signal; a selecting circuit for selecting and outputting the current increasing signal and/or the current reducing signal based on a commutation control signal for changing a polarity at every prescribed electrical angle; a signal synthesizing circuit for synthesizing either the current increasing signal or the current reducing signal selected by said selecting circuit with a current application control signal supplied to a power supply side switching element of said pair of switching elements; a PWM waveform signal generator for outputting a PWM waveform signal based on a current control value; and a PWM synthesizer for synthesizing the PWM waveform signal with a current application direction deciding signal supplied to a ground side switching element of said pair of switching elements.