Patent ID: 8354807
Filing Date: 2013-01-15
Classification: H02P

Abstract:
1. A direct current (DC) brushless motor system without sensor device having two steps startup function including a control device and one end of the control device is connected to an oscillation device, a switching device and one end of the switching device is connected to the control device and the other end is connected to a startup device, a detective device and one end of the detective device is connected to the startup device, a driving circuit and one end of the driving circuit is connected to the detective device and the other end is connected to an external motor and feedbacks to the other end of the detective circuit; wherein the DC brushless motor system is characterized by: when the DC brushless motor system has been activated, the rotation speed of the DC brushless motor system is sequentially achieved in a first predetermined startup rotation speed and a second predetermined startup rotation speed with different frequency so as to achieve a system predetermined rotation; and wherein the detective device is made by a phase detective circuit, a phase rotation circuit, a Back Electromotive Force (BEMF) detector and a frequency detector, and one end of the phase detective circuit is connected to the startup device and the other end is connected to the phase rotation device, and the other end of the phase rotation circuit is connected to one end of the driving circuit, and one end of the BEMF detector is connected to the feedback of the driving circuit and the external motor and the other end is connected to the phase detective circuit and the frequency detector, and the frequency detector is connected to the phase detective circuit.