To eliminate errors of 3-axis magnetoresistive magnetometer, according to its offset errors, sensitivity errors and non-orthogonal errors which specialty was considered, an error compensation model of magnetoresistive magnetometer was established. And the calculation method of the error compensation model, which did not need accelerometers, was proposed to correct the magnetometer errors. The results show the algorithm of error compensation model decrease the root mean square error of the magnetometer from 413nT to 82nT. Thus the 3-axis magnetoresistive magnetometer could fast and accurately measure the geomagnetic field.

AC charging point is one of the main equipment of electric vehicle charging system. The design process of a kind of AC charging point, which is controlled by a Cortex-M3-based microprocessor and μC/OS_II-based management software, is discussed in this paper. Hardware structure and the design principle of each module are described in detail, as well as the important aspects of software design, such as the priority arrangement of tasks and interconnection between tasks. The AC charging point features friendly and easy-to-use user interface, accurate measurement and stable operation, and has obtained the certification from authority department.

The shield based on charging pile port can ensure safe use of charging pile, and it is an important device. For achieving to recognize and process the stuck state of the shield between the shield open and closed, This paper puts forward a method to detect the stuck state, which based on velocity feedback, and designs detection circuit including the limit position and the speed, and determination procedures of the shield’s state of motion. the limit position is detected by photoelectric sensor, and the speed is detected by magnetic sensor. Test result shows that the system can feedback the limit position and the stuck state of the shield instantaneously, and achieve automatic control between the shield open and closed with control correctly and safely.