| 摘要 |
PROBLEM TO BE SOLVED: To provide a braking method which enables quick deceleration without applying a load on software by a method, where a regenerative energy which is generated by braking a motor is consumed in the motor. SOLUTION: An inverter frequency command is reduced once by a deceleration command, to increase a slip value of an induction motor in operation with a minus sign on a generation side (S2), the frequency command is reduced by a set width, only when a DC bus-bar voltage exceeds a set voltage (S10), while the DC bus-bar voltage is monitored (S4 and S5). A deceleration is carried out, while a neighborhood of an operation point, at which a total regenerative energy value from a load side is equal to the loss in the motor, is used. The slippage of the induction motor revolution is decided from a bus-bar voltage detection value and an output current detection and, if the slip is small (S3), an ordinary deceleration state is restored (S23 and S24), DC braking DB is applied (S27) and the motor is stopped (S28) to complete the deceleration. With this constitution, regenerative energy is prevented from penetrating into the inverter side and the rise of the DC bus-bar voltage is suppressed. |
