| 摘要 |
A polyphase induction motor 13 propels an elevator car 10 and is powered by a multiphase inverter 14 which receives power from a battery 16 or a cyclo converter. The inverter is controlled in such a way as to control the frequency and amplitude of the power supplied to the motor in order to control the motor's speed, acceleration, and slip. That inverter control is accomplished by sensing the motor's speed and in response providing predetermined slip and torque signals. These signals are applied to an amplitude and frequency control circuit 22 together with a TACH signal indicative of motor speed. This circuit, Fig. 2, provides polyphase control signals in the form of stepped sine waves at a frequency controlled in response to a comparison of the slip and tach signals and at an amplitude controlled by the torque control (AMPLITUDE) signal. These control signals are applied to a PWM which provides control signals for the inverter. The slip can be controlled over a range which can provide negative slip, by which power is regenerated into a battery 16, and positive slip for motoring torque. <IMAGE> |
