| 摘要 |
<p>PURPOSE:To increase the protective margin of the overvoltage of a filter capacitor while improving regenerative efficiency by changing the characteristics of the quantity of a regenerative brake for a main motor to the voltage value of the filter capacitor in response to the rate of change of the voltage value of the filter capacitor. CONSTITUTION:The voltage of a filter capacitor 4 is detected by a pulse transformer 11. A control circuit 12 arithmetically operates the variation DELTAEc per the unit time of filter capacitor voltage Ec. The variation DELTAEc is output to a subtracter 17 through a dead band circuit 15 and a gain circuit 16. The subtracter 17 outputs a signal Vc acquired by subtracting an output from the gain circuit 16 from a fixed value E0. The fixed value E0 represents a filter-capacitor voltage value where the quantity of a rheostatic brake is maximized on the stationary time. A subtracter 18 outputs a signal obtained by subtracting the filter capacitor voltage Ec from the signal Vc as the quantity PR of a regenerative brake.</p> |
