| 摘要 |
PURPOSE:To keep a torque ripple level constant by providing a matrix circuit for generating three given driving signals and a limiter for limiting the amplitude of said driving signals to a second given value smaller than a first given value. CONSTITUTION:A driving circuit for a brushless motor is composed of Hall elements a1-a3 for generating an output according to the rotation of said motor, first-second controllers b1-b2, an amplifier circuit C, a matrix circuit d, and controllers Su-Sw, to form each-phase output signals Vu-Vw. Further, each of said controllers Su-Sw is composed of said second controller b2, a level shift circuit e, a limiter f for limiting the amplitude of a driving signal to a second given value smaller than a first given value, and an amplifier g. Thus, because a cross point can be determined stably relative to the output of said Hall elements a1-a3, it is possible to keep a torque ripple level constant and to control said torque ripple stably. |
