A DC current sensor for electric vehicle charging billing is designed by using the magnetic modulation scheme of the duty cycle model. Based on the analysis of the working principle of the sensor, the mathematical model of the sensor is given by analytical method. The design principles of the core, coil and circuit parameters are analyzed, and the prototype of the DC current sensor is fabricated and tested. The test results show that the sensor has high measurement accuracy and good stability. Due to the full digital design, the measurement circuit is less interfered by the external electromagnetic environment, suitable in places with complex electromagnetic environment such as new energy vehicle charging piles.
Keywords electric vehicle, DC current sensor, duty cycle, billing