| 摘要 |
PURPOSE:To correct the wrong operation of a zero currnet detector due to a ripple, by passing the input signal of the detector through a notch filter set at the ripple frequency. CONSTITUTION:A notch filter 14 set at the frequency of a ripple contained in the output signal of a main circuit current detecting circuit, which comprises a current converter 10 and a rectifier stack 11, is connected to the output of the detecting circuit. The output signal 14a of the filter is applied to a zero current detector 12 and a current control amplifier 3. The ripple contained in the current signal is thus reduced. As a result, the sensitivity of the zero current detector can be set high and the section of uncontrolled current in switching a conversion unit can be shortened to reduce a motor torque shock due to current jump. |
