Digital Dual-redundant Electric Steering Gear Servo Amplifier

This dissertation is based on the project—the research of digital servo amplifier for rear earth permanent brushless DC motor (BLDCM) with double windings in stator, which is used for Electro-Mechanical Actuator (EMA) in steering engine. The goal is to develop the new amplifier which substitutes for the analog servo amplifier for BLDCM and digital servo amplifier for DC motor.This dissertation introduces the background and significance of the research and the present situation and developing prospect of the EMA Servo amplifier. The paper presents a general design proposal with DSP (TMS320F240) as core controller in accordance with the new amplifier, and introduces the structure and principle of the electric steering engine and dual-redundancy motor. On the basis of the brief introduction of the math model of BLDCM with one winding and double windings, the dynamical mathematics model for BLDCM according to the state equation is provided, some simulation waveforms and results are acquired, meanwhile, the theoretical analysis of some system fault such as inverter switch failure, winding failure and position sensor failure is given. According to the general design, the detailed system hardware and software design is finished, the position servo's digtal control and the function of the double windings' current equalization is realized, the system possesses certain ability of redundancy management and fault tolerant. In order to debug the system conveniently, the author designs the host computer software, adopting C++ Builder, which can realize the various motion styles of BLDCM and displays various dynamical motor statement fed back by client software in real-time mode. Finally, the sample machine is finished and a series of experiments on it are conducted and the results and analysis are also raised. The test shows that this system has the embryonic form of the redundant digital servo amplifier for a EMA and the achievements of the research have very important reference for continual research.