| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric motor driver preventing stop of an inverter due to an excess current and maintaining driving of an electric motor even if load becomes excessive. <P>SOLUTION: The electric motor driver is equipped with: an inverter which is constituted of a bridge structure of a semiconductor switching element, converts DC power into AC power with desired frequency and voltage, and supplies power to the electric motor of a plurality of phases; and an inverter control means giving a driving signal to the inverter so that electric motor current of a prescribed phase difference flows with respect to induced voltage of the electric motor. When the maximum value of an electric motor current exceeds a first current setting value which is previously set, the inverter control means reduces the phase difference at a prescribed time change rate until a first prescribed period elapses. Thus, an operation efficiency of the electric motor is improved and electric motor current is reduced. The stop of the inverter due to the excess current is prevented and driving of the electric motor is maintained. <P>COPYRIGHT: (C)2010,JPO&INPIT |
