The on-board auxiliary inverter is a device that can convert DC power into AC power. This device can convert DC power from a battery or other DC power source into AC power, and provide a stable power supply for electronic devices in the vehicle. In the electric power steering (EPS) system, the required electric motor can be controlled via an auxiliary inverter. Other common applications are: air-conditioner compressor, electric turbocharger and active chassis control. As technology continues to advance, the performance and function of on-board auxiliary inverters will be further improved and refined. The use of SiC devices in on-board auxiliary inverters can decrease the size and loss, reduce the cost and minimize thermal management system, and thus bring more convenience to suppliers and customers.