Efficient 10KW Electronic Driving System for Motors of Electric Vehicles

During past decade, automotive electronics applications exhibited a rapid development. For low pollution and power saving considerations of gas-electric hybrid vehicle, the 300V battery power supply for 600V motor boost converter was needed. Therefore, high efficiency DC/DC and DC/AC converter play important roles for gas-electric hybrid vehicle. GaN has attracted much attention due to their several special properties: fine thermal stability, high breakdown voltage, high electron velocity, and high current density, and so on. GaN could be applied for high frequency and high voltage operation at high temperature environment, especially such as future automobile switching power supply application. In this study, the GaN HEMT for automotive electronics application was developed from SiC growth technology. The GaN buffer layer and active layer will be simulated and optimized based on GaN epitaxy technology. The high current density and high frequency response GaN Schottky diode and enhancement-mode power HEMT will be also fabricated and measured for GaN boost converter IC. For system package issue, we proposed a flip-chip (FC) IC configuration, which we will flip the corresponding HEMT and drive IC onto a protective submount. Many bumps will connect the chip and the submount, and form a dissipation path to sink the excess heat. Since GaN related HEMTs are known to be used in the high frequency and high power environment, this FC structure can further increase their thermal stability. The ultrasonic, thermal bonding processes, and ESD protection circuit will be also studied. During ball grid bumping, ball size, pad metal and submount temperature are all the issues of reliability. For final green 10KW electrical vehicle power system, a 20kW experimental motor-generator set will be first established and a 20kW GaN-based three-phase inverter will then be designed to drive the motor. Then a 20kW GaN HEMT-based power reversible boost converter will be developed to boost the voltage of the vehicle battery over 600V for driving the electric motor. The boost converter can also charge the vehicle battery using the kinetic energy stored in the rotor of the motor when the electric motor is operated at regeneration mode. In addition, the torque and speed control of the electric motor will be realized by the adaptive proportional resonant controller-based field-oriented vector control technique. The switching frequency of the inverter will be designed according to the response speed, conduction resistance, and the parasitic inductance of the HEMT module. This project will finally integrate the GaN HEMT-based boost converter IC and the GaN HEMT-based three-phase inverter IC into a high-efficiency electric motor driver rated over ten thousand Watt.

Project ID:PB10301-1333
External Project ID:NSC101-2632-E182-001-MY3