| 摘要 |
PURPOSE:To simply and effectively reenergize an inverter by synchronously energizing the inverter when the output frequency of the inverter coincides with the rotating frequency of a motor. CONSTITUTION:An inverter operation command signal IP becomes, if recovered, high level ''H'', an inverter is initially reset by a reset signal RS, the rotating frequency fM of the motor is detected by a frequency detector 40, and applied to a frequency voltage controller 11. The controller 11 allows the output frequency of the inverter 10 to coincide in waveform with the output at the frequency as the output frequency is reduced. Then, a ring counter 12 is set by a set signal SE by a setter 60. At this time the content of the counter is set to zero so that the remaining voltage phase coincides with the reference voltage phase. Then, a reference waveform generator 13 generates a reference phase voltage waveform on the basis of the command from the controller 11 and recovers to the operating state before the power is interrupted while obtaining a PWM signal. |
