| 摘要 |
<p>PURPOSE:To prevent the overspeed operation of an induction motor at the slipping time by providing a frequency limiter which limits the output frequency of an inverter to the frequency corresponding to the normal maximum operating speed of an electric rolling stock. CONSTITUTION:A current controller 5 compares a motor current IM with a command value IP and generates a slip frequency command fS. An inverter frequency command generator 7 adds a rotating frequency fR and the slip frequency command fS and generates an inverter frequency command f0. A low priority circuit 9 judges the low priority of the command f0 and the maximum frequency fMAX of the inverter corresponding to the preset normal maximum speed of an electric rolling stock. The output of the circuit 9 is applied as a frequency command to an inverter 2, and also applied as a voltage command to the inverter 2 through an f/V converter 8.</p> |
