A SiC MOSFET Isolated DC/DC Converter for a Hybrid Vehicle

Abstract

This article deals with development of a DC/DC converter for use as a device for charging the traction storage batteries of an unmanned vehicle with a solid-oxide fuel cell stack. A phase shift controlled 8 kW full-bridge DC/DC converter was modeled, developed, manufactured, and tested within the frame of a research work. The device operation principle is described. The device control system developed on the basis of the Cortex ARM STM32F407VGT6 controller uses original software. The software supports the converter operation in an automatic mode by receiving, from the central processor device, operation mode setting commands (including the current, voltage, and power setpoints) and transmitting the remote measurement data (input and output circuit voltages, and the power switches and housing temperatures). Communication with the vehicle central processor is performed using the CAN protocol as per the SAE J1939 standard. The CAN is a standard serial communication protocol (its support for real-time distributed control with multiplexing allows information to be exchanged between various vehicle components). The classic CAN frame format allows data transmission rates up to 1 Mbps and payloads up to 8 bytes per frame. However, the recently introduced format (a CAN flexible data transmission rate frame format) allows higher data transmission rates and payloads higher and longer than these ordinary values. The transmission rate in the developed converter is 250 kbps. The converter operates in the input voltage range from 180 to 250 V and output voltage range from 500 to 800 V. The output current limit is 10 A. The converter efficiency was estimated to be 93%.