| 摘要 |
PURPOSE: To limit the reduction rate of conduction current of an element even in an extremely low output frequency range by controlling the output voltage reference of a DC power supply based on a set speed delivered from an external speed reference circuit and a DC voltage value and then controlling the output frequency reference of an inverter based on the set speed and the rotational speed. CONSTITUTION: A voltage reference circuit 2 is a circuit for controlling the output voltage reference of a DC power supply 1 based on the set speed P outputted from an external speed reference circuit 6 and an AC voltage value DV. A speed reference circuit 4 connected with the external speed reference circuit 6 and a rotational speed detector 8 controls the output frequency reference of an inverter 3 based on the set speed P and a rotational speed R. An AC motor 5 is controlled by the inverter and the speed thereof is fed from the external speed reference circuit 6 to the speed reference circuit 4. The external speed reference circuit 6 also delivers a signal to the voltage reference circuit 2 of the DC power supply 1 in order to control the output voltage thereof. |
