Patent ID: 6229719
Filing Date: 2001-05-08
Classification: H02P

Abstract:
An inverter control method of converting a dc power into an ac power having a variable frequency and a variable voltage according to an output frequency instruction and output voltage instructions of an inverter to control an ac motor at a variable speed, comprising the steps of:inputting to an input point a current detection value of one phase of the ac motor and current estimation values of other phases thereof;converting the current detection value and the current estimation values into a rotating coordinate system according to a reference phase obtained by integrating the output frequency instruction of the inverter to obtain instantaneous values respectively of a torque current and an exciting current;inputting average values respectively of the instantaneous values;converting the values into a fixed coordinate system according to the reference phase to obtain the current estimation values of the other phases and feeding the values back to the input point; andcontrolling an output voltage or an output frequency of the inverter according to the instantaneous value or the average value of the torque current.