Electric Power System Control Unit Development

EPS is a kind of power steering system following the system of hydraulic, motor was adopted to offer power directly. EPS has many advantages such as adjusted power which is controlled by the automatically controlling unit,good way sense,environmental protection,low energy consumption, convenient maintenance .The development trend of intelligent vehicles, future security requirements and environmental requirements was fully represented by EPS.In this thesis the Electronic Control Unit (ECU) and the software program of the ECU was designed, control strategies and algorithm were also studied based on the study of the operation principles of EPS. Following is the detailed process:1. Basic components, working principle and mathematical model of Brushless DC Motor (BLDCM) were described in detail.2. While the functions of ECU were considered, a scheme of motor control based on the high-performance microcontroller 80C552 was put forward and the ECU was designed. PWM technique was used to control H and closed loop motor current.3. Three control strategies which are assisting mode return ability and damp mode to get a stable steering under various conditions was presented and discussed in this paper. And a control algorithm based on PID was proposed under the strategies.4. The software program of function modules were completed based on the designed experimental ECU; the rationality and the feasibility of the warning function of the electronic control unit were proved; circuit boards were produced, simulation tests have been built up.The research above make the A /D acquisition program, speed signal acquisition program of the Electric power steering system come true, and t it laid a practical basis for the next preliminary technology.