| 摘要 |
<p>PURPOSE:To reduce the thermal capacity of a brake resistor, by providing a limiter to a field current control circuit while considering the increment of resistance of the brake resistor. CONSTITUTION:Field current 1f is compared with a field current pattern 1f0 corresponding to a speed (v) in a comparator 12, which provides a differential output DELTAif1 to a comparator 15. On the other hand, an armature current (ia) is compared with an armature current pattern (ia0) corresponding to the speed (v) in a comparator 14, which provides a differential output DELTAia1 to the comparator 15. The comparator 15 compares the differential outputs DELTAif<1> and DELTAia1 and provides a differential output DELTAif2 to a comparator 18. A field current limiter generator 17 outputs a limiter signal DELTAifm corresponding to the speed (v). The comparator 18 limits the differential output DELTAif2 below the limiter signal DELTAifm and provides a phase shift angle command alphaF to a phase shifter 16. By such arrangement, increase of the size of a brake resistor can be suppressed.</p> |
