Research On Commutation Process And Angular Position Detection Of Permanent Magnet Brushless DC Motor

As a electric mechanical converter, Motor has been widely used over one century ranging from every field of national economy to people's everyday life. The Permanent-Magnet Brushless DC motor (BLDCM) has the merits of both Brush DC motor and asynchronous motor. Because Permanent-Magnet BLDCM has the advantages of high power-density, high efficiency, high rate between torque and current, simpleness for control, it has been talent showing itself in motor drives family for recent years and widely used in every industry area especially in speed-variable applications and servo systems.Firstly, this thesis analyzes the operational principle of the Permanent-Magnet BLDCM. Then, it deduces the key parts of BLDCM's control system, with introducing their hardware and software design.The methods of rotor position detection of Permanent-Magnet BLDCM are introduced in this paper, and an angular position detection unit based on resolver and AD2S83 is presented. The paper describes how to select the external components for AD2S83 after analyses how it works.With thyristor-based converter, the main circuit under investigation is different from conventional ones. To achieve successful and optimal turn-off of thyristors, special designed circuit topology is adopted in our system, and an in-depth study of the commutation process and components selection is developed then.The thesis makes the comparison of some different key parameters. Their influences on the commutate surge current and commutate time are discussed. And some important waveforms are recorded. It comes to a conclusion, and optimizes the strategy of control system. Moreover, the comparison validates the correctness of the conclusion in this thesis.