| 摘要 |
<P>PROBLEM TO BE SOLVED: To observe an input voltage limit into a load device, relating to a power supply unit equipped with a voltage conversion part for varying the input voltage to the load device. <P>SOLUTION: A step-up/down converter 12 includes switching elements Q1 and Q2, which are switched according to switching control signals S1 and S2 from a control unit 30 for conversion operation to a DC voltage according to a voltage command value, and a reactor L1 which is connected to a current path between a power supply line 6 and a DC power source B, wherein a voltage switched by the switching element is applied to both ends. The control unit 30 includes a voltage command generating part for generating a voltage command value, according to a drive force required for an AC motor M1, and a voltage command correcting section for lowering the voltage command value according to the power fluctuation frequency of the AC motor M1 so that the system voltage VH does not exceed the input-voltage limiting value into an inverter 14, based on the relation between the power fluctuation frequency of the AC motor M1 and the resonance frequency of a power supply unit 10#. <P>COPYRIGHT: (C)2011,JPO&INPIT |
