TORQUE-RIPPLE REMOVAL CIRCUIT OF THREE-PHASE BRUSHLESS DC MOTOR

摘要

PURPOSE: To provide the torque-ripple removal circuit, of a three-phase brushless DC motor, wherein it removes torque ripples with good accuracy and its input offset voltage is small. ;CONSTITUTION: Torque-ripple-removal-signal generation means 600, 24 to 29 generate the difference signal between the sum of three-phase-half-wave signals out of sinusoidal-wave-three-phase driving signals supplied to stator windings 17 to 19 and a DC signal which has multipled a three-phase-half-wave-signal- amplitude value by SIN(π/3). A modulation circuit 28 amplitude-modulates output signals of the torque-ripple-removal-signal generation means by a torque instruction. According to the output signal of a torque-instruction-error amplification means 22 in which a torque instruction control signal is input to a noninversion terminal and in which the sum of the inversion output of the modulation circuit 28 and a motor-total-current signal (the both-end voltage of a resistance 20) is input and amplified, the amplitude value of a phase driving signal is controlled by a current amplification circuit 10. The phase driving signal of the current amplification circuit 10 is supplied to transistors 11 to 16 whose collectors have been connected respectively to the stator windings 17 to 19.;COPYRIGHT: (C)1994,JPO&Japio