| 摘要 |
<p>An AC elevator control system has a converter for converting a three-phase AC power to a direct current, an inverter for inverting the direct current to a three-phase AC power with a variable voltage at a variable frequency, and a three-phase induction motor for receiving the last-mentioned AC power to operate an elevator car connected to a counterweight through a traction rope trained over a sheave. A battery connected across the DC side of the inverter is enabled upon the occurrence of a power failure or a fault. A command emergency frequency generator responds to the occurrence of an emergency such as a power failure to deliver to the inverter a low frequency emergency frequency as determined by the relationship between a difference in weight between the elevator car and the counterweight and various losses of a motor driving system so as to cause the induction motor not to generate regenerative power.</p> |
