| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of excessive current caused by half fractional harmonic resonance.SOLUTION: A control device 1 has a circuit equivalent to an LCR series circuit having an inductor component, a capacitor component and a resistor component which are connected to one another in series. The controller 4 performs chipping control on current to flow through the circuit by a switch 9, thereby operating average current or voltage to be supplied to an electric motor 2 connected to the output side of the circuit to control the control amount of the electric motor 2. The controller 4 sets the chopping control frequency for the switch 9 to the same value or more of a frequency f3 at which one-third fractional harmonic resonance starts to occur so that the current to be supplied to the circuit is in a range where the half fractional harmonic resonance does not occur, the frequency f3 being confirmed by actual measurement or calculation.SELECTED DRAWING: Figure 10 |
