| 摘要 |
PURPOSE:To improve efficiency of utilization of inverters and motors by making the output voltage of a variable-voltage variable-frequency power supply constant in the region wherein the frequency exceeds a specified value. CONSTITUTION:A frequency control system which controls the output frequency of an inverter gives a speed instruction signal or an inverter output-voltage signal to a voltage frequency-characteristic regulation circuit 8 through an acceleration and decelation regulator 4. The output of the regulation circuit 8 is given to a voltage- frequency converter 9, and the frequency signal controls the ON-OFF cycle of the main-circuit element of the main portion of an inverter 1. The regulation circuit 8 has voltage-regulating characteristics, and limits the output voltage to a specified value in the case the output frequency of the inverter is controlled above a specified value. In this constitution, the output power can be constantly controlled within the frequency region whose values exceed the specified value of the characteristics, and efficieny of utilization of motors can be improved for loads having constant-output characteristics. |
