Brushless DC motor drive circuit, brushless DC motor and equipment

摘要

PPROBLEM TO BE SOLVED: To provide a brushless DC motor drive circuit wherein noise arising from switching of a high-voltage inverter and switching of a low-voltage control circuit, which is superposed on an instantaneous value of the direct-current voltage of the inverter, is directly removed and torque ripples of a motor are reduced and to achieve the same noise performance, shape, and size as those of an induction motor by incorporating this brushless DC motor drive circuit. PSOLUTION: A higher-order frequency component of power supply fluctuation in a PWM signal generation unit 10 is subjected to effective correction. A motor structure (enclosure) 29 includes a rectification circuit 2, an inverter main circuit 5, a voltage dividing circuit, a direct-current voltage detection unit 8, a magnetic pole position sensor 4, a rotor position detection unit 7, an output voltage computation unit 9, and the PWM signal generation unit 10. The shape and size of the motor structure 29 are substantially the same as those of the induction motor of the same output. Therefore, it is possible to reduce noise from and the size of a brushless DC motor equipped with the drive circuit and an apparatus mounted therewith. PCOPYRIGHT: (C)2011,JPO&INPIT