Implementation of Digital Bidirectional Buck-Boost Converter with Changeable Output Voltage for Electric Vehicles

In recent years, with the development of science and technology, the number of means of transportation has increased rapidly, resulting in air pollution. Therefore, electric vehicles have been developed to replace petrochemical energy, such as hybrid vehicles, electric vehicles, etc. Therefore, a four-switches bidirectional non-inverting buck boost converter is proposed for the mobile power grid of electric vehicles. The digital converter with changeable multiple output voltage level and digital compensator with voltage feedback is realized by digital controller dsPIC33FJ16GS502 of microchip company. The transfer function of open loop model and closed loop model is compared to confirm the loop gain stability by using Mathcad and Simplis. Finally, the proposed digital bidirectional buck-boost converter is implemented. Its input voltage is 48V of the bus voltage, and changeable output level is 12V, 24V, 36V, 4SV and 72V, respectively. The prototype circuit has both maximum power of 300W and maximum efficiency of 97%.