| 摘要 |
PROBLEM TO BE SOLVED: To improve the electric source power factor by generating the reactive power of leading phase cancelling the reactive power in the electric source by obtaining the reactive power outputting possible capacity in a power converter according to the load of an electric motor, limiting the leading reactive power reference cancelling the reactive power obtd. with a reactive power detector and controlling the leading reactive power in the power converter. SOLUTION: The power converter is composed of a pulse width modulator type converter/inventor for controlling the power factor of the power and the reactive power output possible capacity is obtd. by subtracting the changed load power of the electric motor from the rated capacity. The reactive power control function obtains the leading reactive power reference D to cancell the difference according a differential device 21 for obtaining the difference between the target value A of the reactive power control and the reactive power B and the obtd. reactive power control deviation C. The allowance capacity E is obtd. by refering the graph approximately displaying the relation between the load ratio G and the output possible reactive power reference F. The min. capacity in the existing power converter is effectively used and the power factor of the electric source can be improved. |
