| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive device which can stably detect phase current of a three phase motor by a one shunt system with simple algorithm and in which sampling means can be used for other purposes and for a plurality of motors. <P>SOLUTION: A modulation pulse of three phases is generated by a duty ratio corresponding to a voltage level which is to be applied to respective coil terminals 27. At least one of prescribed amounts d11 and d12 is selected as a first shift amount d1 in accordance with pulse width V1 of the longest pulse in the modulation pulses of the three phases. The second longest pulse in the modulation pulses of the three phases is shifted backward by the first shift amount and timing is delayed. The third longest pulse is shifted backward by the prescribed second shift amount and timing is delayed. Respective coil ends (U, V, W) are pulse-driven by performing switching by the modulation pulses of the three phases, on which a shift result is reflected. <P>COPYRIGHT: (C)2012,JPO&INPIT |
