Method and device for detecting position of rotor of brushless motor

The invention relates to a method and a device for detecting the position of a rotor of a brushless motor, which are characterized in that a rotary transformer and the rotor of a tested brushless motor are arranged coaxially, the rotary transformer outputs two paths of orthogonal high-frequency sine-cosine signals containing information about the position of the rotor, and the information about the position of the rotor is obtained by the methods such as signal conditioning or resolving and the like. The most widely applied integrated chip at present adopting a special Resolver-to-Digital converter (RDC for short) and the like and a peripheral configuration circuit are used for performing resolving, and a special resolving chip of the type is sensitive to signals and has no fault-tolerant function, so the reliability is difficult to guarantee. The device of the invention is provided with a simple signal conditioning circuit on the basis of an RDC functional circuit to realize the detection of the position of the rotor of the brushless motor with self-monitoring and fault tolerance functions.