For the conventional vehicle, an efficient and effective heat source that provides autonomous exhaust temperature control is of interest, and one solution is a diesel burner which needs to adjust its air delivery based on transient operating conditions through a three-phase motor drive system powered by a 12V lead-acid battery. The system proposed in this paper consists of a series-resonant LLC MOSFET full-bridge converter, which provides high-efficiency energy transfer through implementing Zero Voltage Switching, and an IGBT inverter which provides the high-side phase currents to a 1kW brushless DC motor. Experimental results on this prototype system demonstrate the LLC DC/DC part efficiency is 97.6% and the inverter efficiency is 92%.