| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent generation of noise while preventing overheat of an inverter when an AC motor is locked. <P>SOLUTION: When an AC motor is locked, vector switching control is performed to vary the current vector of the AC motor such that loss of an inverter is reduced by increasing loss of the AC motor thus avoiding concentration of current on a specific switching element of the inverter. In the vector switching control, torque of the AC motor is held constant by switching a command current vector in the order of current vectors i0, i1 and i2 thereby increasing reactive power of the AC motor periodically. The current vector i0 generates a torque slightly smaller than the maximum torque, and the current vectors i1 and i2 generate a torque identical to that of the current vector i0 and increase reactive power as compared with the current vector i0. <P>COPYRIGHT: (C)2008,JPO&INPIT |
