| 摘要 |
PURPOSE:To operate the backward inverter in normal condition even in the state the synchronous motor needs no generation torque, by a method wherein the commutation lead angle of the commutatorless motor is controlled in response to the load in case the magnitude of the motor current is at the specified value or less. CONSTITUTION:The signal of the position detector 5 is converted into the analogue quantity through the speed detection circuit 10, has the deviation to the speed reference value N* corrected and is delivered to the speed control circuit 6. This output I* has the deviation to the greatest lower band current value Ic* corrected through the switching circuit 18, and when ¦I*¦>Ic*, I is made to be the current reference input and when ¦I*¦<Ic*, I* is made to be the current reference input, and thereby, the current value control is performed through the power rectifier 1. A saw tooth wave P is obtained from the speed analogue signal by means of the V/F convertor 11, the counter 12 and the D/A converter 13. And then, a signal, which changes the phase lag from the position detection signal by means of the current reference input I* or Ic*, is obtained through the level comparison, the level detection circuit 14 and FF15. This output permits betao of the power converter to change. |
