| 摘要 |
<p>PURPOSE:To eliminate a voltage detector by utilizing as a motor voltage the voltage generated from simulating voltage generating means for simulatively generating a voltage when a motor is regenerative at the time of switching the series connection as a light load is regenerative. CONSTITUTION:A comparator CMP1 compares a regenerative brake command VBP with a real brake force VB to decide the conduction rate gamma of a field chopper. When it becomes a reference voltage VES < detecting voltage VEL, a trolley wire limiter operates to apply its differential voltage to the comparator CMP1 to reduce the conduction rate gamma of the chopper. As a light load regeneration is detected when a series connection is switched, a logic circuit LG detects it to close a switch SW, and the difference between the simulating trolley wire voltage VEL from a simulating voltage generator VG and the voltage VEL is applied to the comparator CMP1.</p> |
