| 摘要 |
Open loop methods are commonly used to start a motor, increasing the frequency until the EMF can be detected and a reliable transition to sensorless control can be made. It is the purpose of this invention to disclose an observer, operating during a time when open loop control is being used to drive a synchronous motor, the output of the observer being a signal, E_I_angle, related to the angle between a rotational EMF vector and the current excitation vector, the observer determining the angle by an iterative calculation incorporating a summation term, the summation term summing the variation of the quadrature component of a rotational EMF vector relative to an estimated EMF position vector, and using the angle output of the observer to update the estimate of the rotational EMF position vector. In a further aspect of the invention the observer output signal, E_I_angle,can be used to determine the transition to closed loop control, when the observer output signal reaches a value indicating conditions close to pull out conditions. |
