Method and device for detecting position of rotor of brushless motor

Abstract

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.

Description

technical field [0001] The invention relates to a method and a device for detecting the rotor position of a brushless motor, belonging to a method and a device for detecting the rotor position of a brushless motor control system. Background technique [0002] One of the key technologies of the brushless motor control system is the detection of the rotor position. Only after the actual spatial position (absolute position) of the rotor is detected, the control system can determine the power-on mode, control mode, and frequency and phase of the output current of the inverter. To ensure the normal operation of the brushless motor. Therefore, an accurate rotor position detection device is very important. Once the position detection device fails, the commutation logic of the motor will be confused, the output torque will decrease, the speed will decrease until it stops. In some occasions with high reliability requirements or certain specific occasions, such as: national defense,...

AI Technical Summary

Problems solved by technology

The absolute grating encoder directly converts the angle of the rotating shaft into a digital signal, which is simple and convenient to use, but it is difficult to be widely used due to factors such as environmental adaptability and price; the Hall sensor has a simple structure, but it is difficult to meet the requirements of high-precision angle measurement and is limited. Resolvers are widely used in high-precision servo systems due to their reliable structure, good real-time performance, and strong environmental adaptability.

[0004] At present, in a large number of documents and patents at home and abroad, the research on the rotor position detection of brushless motors is limited to the conditioning method of the position signal, and the research on the reliability of the rotor position detection of brushless motors is limited to the Hall position sensor. The rotor position detection method of the brushless motor of the transformer is difficult to meet the high reliability requirements of national defense and aerospace.

[0005] When a resolver is used as the rotor position detection device of a brushless motor, the resolver outputs two high-frequency sinusoidal signals that contain rotor position information and are orthogonal to each other. The rotor position information must be obtained through signal conditioning or calculation methods, which is currently the most widely used. It is widely used integrated chips such as dedicated Resolver-to-Digital Converter (RDC) plus peripheral configuration circuits for solving. Such special solving chips are sensitive to signals and have no fault tolerance function, so the reliability Difficult to guarantee

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