| 摘要 |
PURPOSE:To carry out stable controlling with slight speed change of a motor by operating an induction motor within a discharge pressure controlling range according to a preset rotational speed of a compressor, based on a signal from a pressure detector at a discharge port of the compressor. CONSTITUTION:In respect to an air-conditioning load within an area where a load of a compressor is light and a discharge pressure is low, a target speed of an induction motor 1 is determined by a speed command generator 9. A speed command NR is input to a controller 10, and acceleration is carried out every time interval T. When the speed coincides with the target speed command NR, the acceleration is stopped and the induction motor 1 is rotated with a constant rotational speed NR. When the air-conditioning load is heavy, an acceleration/deceleration value N of the motor 1 every time interval, approx.< is determined by the controller 10 for controlling, according to deviation between a discharge pressure limited value Pd(max) and an actual discharge pressure Pd of the compressor 2 detected by a pressure detector 3. That is, the acceleration/deceleration rate of the induction motor 1 is varied according to the deviation of the discharge pressures. A limiter is provided for a maximum value of the acceleration/deceleration rate. |
