| 摘要 |
PROBLEM TO BE SOLVED: To provide a speed controller for starting a PWM inverter supplying power to an induction motor surely or restarting it surely at recovery from instantaneous power interrupt. SOLUTION: One of voltage generating means 21, 31, 41, 51, adders 22, 23, a rotational speed operating means 24, a rotational direction determining means 25, and a multiplier 26 are provided additionally, and the voltage generating means is operated for a specified interval at starting or restarting. Consequently, self-excited oscillation takes place in a control system comprising the voltage generating means, an induction motor 1, and a PWM inverter 2. The rotational speed operating means 24 and the rotational direction determining means 25 obtain information on the rotational direction and speed of induction motor 1 from the primary current thereof for α, βaxis components of a fixed coordinate, and the PWM inverter 2 is started based on that value. |
